General Surgery
Final Professional MBBS — General Surgery. Explanation-first answers that teach the reasoning behind every fact, with classifications, comparison tables, drug doses, clinical pearls and key-point recaps from Bailey & Love and SRB's Manual.
THE CONCEPT
Malignant melanoma is a malignant tumour of melanocytes — the pigment-producing cells of the skin. Although it accounts for a minority of skin cancers, it is by far the most dangerous because it metastasises early and widely. Its incidence is rising, and it is strongly linked to ultraviolet (sun) exposure. The key to a good outcome is early recognition and excision before it invades deeply.
RISK FACTORS
Risk factors include ultraviolet exposure (especially intermittent intense exposure and sunburn), fair skin that burns easily, multiple or atypical (dysplastic) naevi, a family or personal history of melanoma, immunosuppression, and a giant congenital naevus.
RECOGNITION — THE ABCDE RULE
A changing mole is assessed with the ABCDE criteria:
- A — Asymmetry
- B — Border irregularity
- C — Colour variation (several shades)
- D — Diameter > 6 mm
- E — Evolution (change in size, shape or colour)
Additional warning symptoms are itching, bleeding, crusting or ulceration of a pigmented lesion.
TYPES
The main subtypes are superficial spreading (commonest), nodular (aggressive, grows vertically early), lentigo maligna melanoma (on sun-damaged skin of the elderly face), and acral lentiginous (on palms, soles and under nails — the commonest type in darker-skinned people).
PROGNOSIS & SPREAD
The single most important prognostic factor is the Breslow thickness — the depth of the tumour in millimetres (the deeper the tumour, the worse the prognosis); ulceration and mitotic rate also matter. Melanoma spreads by lymphatics (to regional nodes) and by blood, and is notorious for being able to metastasise to almost any organ (liver, lung, brain, bone), sometimes years later.
INVESTIGATION & MANAGEMENT
Diagnosis is by excision biopsy of the whole lesion (to allow accurate measurement of Breslow thickness), followed by staging (sentinel lymph node biopsy for staging, and CT/PET for advanced disease). Management is:
- Wide local excision — with the margin determined by the Breslow thickness.
- Sentinel lymph node biopsy to stage the nodal basin; lymph node dissection if involved.
- Advanced/metastatic disease — immunotherapy (checkpoint inhibitors such as pembrolizumab, nivolumab, ipilimumab) and, for BRAF-mutant tumours, targeted BRAF inhibitors (e.g. vemurafenib).
💡CLINICAL PEARL: Two facts dominate: use the ABCDE rule to recognise a suspicious mole, and know that Breslow thickness (depth) is the most important prognostic factor. Diagnosis is by excision biopsy (never a shave/partial biopsy that prevents depth measurement), and melanoma can metastasise to any organ, which is why early excision matters so much.GROWTH PHASES & WHY DEPTH MATTERS
Understanding the two growth phases explains why Breslow thickness is so powerful a predictor. Melanoma initially grows in a radial (horizontal) phase, spreading within the epidermis (in situ) and superficial dermis, during which it has little metastatic potential. It then enters a vertical (invasive) phase, penetrating deeper into the dermis and gaining access to lymphatics and blood vessels — and hence the ability to metastasise. Since Breslow thickness measures exactly this depth of vertical invasion, it directly reflects the tumour's access to the routes of spread, which is why it dominates prognosis and dictates excision margins.
STAGING & THE SENTINEL NODE
Staging uses the TNM system, and the sentinel lymph node biopsy is a key concept: the 'sentinel' node is the first node draining the tumour's territory, identified using a dye and radioactive tracer. If this first node is free of tumour, the rest of the basin is very likely free too, sparing the patient a full dissection; if it contains tumour, it upstages the disease and guides further treatment. This elegant technique provides accurate staging with minimal morbidity.
THE REVOLUTION IN ADVANCED DISEASE
Historically metastatic melanoma was almost untreatable, responding poorly to chemotherapy and radiotherapy. The management has been transformed by two developments: immune checkpoint inhibitors (anti-PD-1 agents such as pembrolizumab and nivolumab, and anti-CTLA-4 ipilimumab), which release the brakes on the immune system to attack the tumour; and targeted therapy with BRAF (and MEK) inhibitors for the roughly half of melanomas carrying a BRAF mutation. These have produced durable responses in a disease that was once rapidly fatal.
A NOTE ON AMELANOTIC & OCCULT MELANOMA
A clinical trap worth knowing is the amelanotic melanoma — a melanoma that produces little or no pigment and therefore appears as a pink or flesh-coloured nodule rather than a dark lesion, easily mistaken for something benign. Melanoma can also arise at hidden sites — under a nail (subungual), on the sole, in the eye (uveal melanoma), or on mucosal surfaces. Occasionally it presents first as a metastasis (e.g. an enlarged node) from an unknown or regressed primary. These atypical presentations are why any changing, atypical or unexplained lesion deserves careful assessment.
💊KEY POINTS / NUMBERS (viva)- ABCDE: Asymmetry, Border, Colour, Diameter >6 mm, Evolution.
- Breslow thickness (depth in mm) is the most important prognostic factor; excision biopsy for diagnosis.
- Wide local excision (margin by Breslow) + sentinel node biopsy; advanced → immunotherapy/BRAF inhibitors.
🔑KEY POINTS TO REMEMBER- Malignant melanoma = malignant tumour of melanocytes; most dangerous skin cancer (early, wide metastasis); UV-related.
- Recognise with ABCDE (Asymmetry, Border, Colour, Diameter >6 mm, Evolution) + itching/bleeding.
- Types: superficial spreading (commonest), nodular (aggressive), lentigo maligna, acral lentiginous (dark skin).
- Breslow thickness (depth) is the most important prognostic factor; diagnose by excision biopsy; can metastasise to any organ.
- Wide local excision (margin by depth) + sentinel node biopsy; advanced → immunotherapy (checkpoint inhibitors)/BRAF inhibitors.
📚SOURCES: Bailey & Love's Short Practice of Surgery; SRB's Manual of Surgery.THE CONCEPT
The two common non-melanoma skin cancers — basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) — both arise from keratinocytes of the epidermis and are strongly related to cumulative ultraviolet (sun) exposure. They are far commoner and generally far less dangerous than melanoma, but they behave differently from each other, and the key distinction is their tendency to metastasise.
BASAL CELL CARCINOMA (RODENT ULCER)
BCC is the commonest skin cancer, arising from the basal layer of the epidermis, typically on sun-exposed skin of the face (classically above a line from the angle of the mouth to the ear). Its defining behaviour is that it is locally invasive but very rarely metastasises. The classic nodular BCC is a slow-growing 'rodent ulcer' — a pearly nodule with a rolled, beaded edge, surface telangiectasia and central ulceration. Other types are superficial and morphoeic. Treatment is surgical excision with a margin, Mohs micrographic surgery for the face or recurrent lesions, and radiotherapy or topical therapy in selected cases.
SQUAMOUS CELL CARCINOMA
SCC also arises on sun-exposed skin but, unlike BCC, can metastasise (to regional lymph nodes). It frequently develops from precursor lesions — actinic (solar) keratoses and Bowen's disease (SCC in situ) — and can arise in chronic wounds, scars and sinuses (a Marjolin's ulcer). It presents as a keratotic, crusted or ulcerated nodule with an everted, raised edge. Risk is increased by sun exposure, immunosuppression and chronic inflammation. Treatment is excision with an adequate margin (or radiotherapy), with treatment of involved nodes.
BCC VS SCC
Feature BCC SCC Frequency Commonest skin cancer Second commonest Metastasis Very rarely (locally invasive) Can metastasise to nodes Appearance Pearly nodule, rolled edge, telangiectasia ('rodent ulcer') Keratotic/ulcerated nodule, everted edge Precursors — Actinic keratosis, Bowen's disease, Marjolin's 💡CLINICAL PEARL: Fix the two pictures: BCC is the 'rodent ulcer' — a pearly nodule with a rolled edge and telangiectasia that is locally destructive but almost never metastasises; SCC has an everted edge, can metastasise to nodes, and arises from actinic keratosis, Bowen's disease or a Marjolin's ulcer. Both are UV-related and treated primarily by excision.PRECURSOR & PREMALIGNANT LESIONS
An important theme with SCC is its development from recognisable premalignant lesions, which offers a chance for early treatment. Actinic (solar) keratoses are rough, scaly patches on sun-damaged skin that carry a small risk of progressing to SCC; Bowen's disease is SCC in situ — a persistent red scaly plaque confined to the epidermis. Recognising and treating these (with cryotherapy, topical agents or excision) can prevent invasive cancer, and their presence signals a field of sun-damaged skin at risk of further tumours.
THE ROLE OF IMMUNOSUPPRESSION
A clinically important point is the marked increase in non-melanoma skin cancer — especially SCC — in immunosuppressed patients, particularly organ transplant recipients on long-term immunosuppression. In these patients SCCs are more numerous, more aggressive and more likely to metastasise. This underlines the role of immune surveillance in controlling these UV-driven cancers, and means such patients need regular skin surveillance and prompt treatment of any suspicious lesion.
MOHS SURGERY & MARGIN CONTROL
Mohs micrographic surgery deserves explanation as it is frequently mentioned for BCC. It involves excising the tumour in thin layers, each examined microscopically at the time until a completely clear margin is achieved. This gives the highest cure rate while sparing the maximum normal tissue, making it ideal for tumours on the face (where tissue conservation matters cosmetically), at high-risk sites, and for recurrent or morphoeic BCCs with ill-defined margins.
A NOTE ON PREVENTION & SUN PROTECTION
Because non-melanoma skin cancers (and melanoma) are so strongly driven by ultraviolet exposure, prevention is an important, examinable dimension. Advising sun avoidance at peak times, protective clothing and hats, broad-spectrum sunscreen, and avoidance of sunbeds reduces the cumulative UV damage that causes these tumours. Public education and, in high-risk individuals (fair skin, prior skin cancer, immunosuppression), regular skin surveillance for early detection complete a prevention-and-screening strategy that materially reduces skin-cancer burden.
💊KEY POINTS / NUMBERS (viva)- BCC = commonest skin cancer; 'rodent ulcer' (pearly, rolled edge, telangiectasia); locally invasive, rarely metastasises.
- SCC = can metastasise to nodes; everted edge; from actinic keratosis/Bowen's/Marjolin's ulcer.
- Both UV-related; treat by excision (Mohs for facial/recurrent BCC); treat nodes in SCC.
🔑KEY POINTS TO REMEMBER- BCC and SCC = non-melanoma skin cancers from keratinocytes; UV-related; less dangerous than melanoma.
- BCC: commonest skin cancer; 'rodent ulcer' (pearly nodule, rolled/beaded edge, telangiectasia); locally invasive but rarely metastasises.
- SCC: can metastasise to lymph nodes; everted edge; arises from actinic keratosis, Bowen's disease (in situ) or Marjolin's ulcer.
- Treat both by excision with a margin (Mohs for facial/recurrent BCC; radiotherapy an option); treat involved nodes in SCC.
📚SOURCES: Bailey & Love's Short Practice of Surgery; SRB's Manual of Surgery.THE CONCEPT
The systematic examination of a lump or swelling is a fundamental surgical skill, because the physical characteristics of a swelling usually reveal its nature — cystic or solid, benign or malignant, and the tissue from which it arises. The approach is the classic sequence of inspection, palpation, percussion and auscultation, supported by a focused history, ending with examination of the regional lymph nodes.
HISTORY
The history establishes the duration and mode of onset, any change in size, pain, and associated symptoms (and whether there are other similar lumps or systemic features).
INSPECTION
Inspection notes the swelling's site, size, shape, surface, colour, and the state of the overlying skin (and whether it moves with respiration, swallowing or protrusion of the tongue where relevant).
PALPATION — THE HEART OF THE EXAMINATION
Palpation systematically assesses:
- Site, size, shape, surface and edge, and consistency (soft, firm, hard or cystic).
- Temperature and tenderness.
- Fluctuation and a fluid thrill (indicating a cystic, fluid-filled swelling).
- Transillumination (a fluid-filled swelling lights up — e.g. hydrocele, cystic hygroma).
- Pulsatility and expansility (an aneurysm expands in all directions), and compressibility/reducibility (a vascular malformation or a hernia).
- Relation to skin and deeper structures — the plane (tissue layer) of the swelling and its mobility or fixity.
- A cough impulse (hernia).
DETERMINING THE PLANE
Identifying the tissue layer of origin is central: a swelling in the skin moves with the skin; a subcutaneous swelling moves freely over deeper structures; an intramuscular swelling becomes less mobile when the muscle is contracted; and a swelling arising from bone is fixed.
COMPLETING THE EXAMINATION
Finally, auscultate for a bruit (vascular swelling), and always examine the regional lymph nodes (and, for a suspected malignancy, look for hepatomegaly and general lymphadenopathy). From these findings a differential is built — for example, fluctuation with transillumination suggests a cystic lesion, while a pulsatile expansile mass suggests an aneurysm.
💡CLINICAL PEARL: The examinable framework: after the history, inspect then palpate, assessing site, size, shape, surface, consistency, edge, fluctuation, transillumination, pulsatility, compressibility, mobility and plane, then auscultate and examine the regional lymph nodes. Two quick rules: fluctuation + transillumination = a cystic (fluid) swelling, and a pulsatile, expansile mass = an aneurysm.SPECIFIC MOVEMENTS & THEIR MEANING
Certain swellings show characteristic movements that instantly narrow the diagnosis, and these are examiner favourites. A thyroid swelling moves up on swallowing (because of its attachment to the larynx via the pretracheal fascia); a thyroglossal cyst moves up on protruding the tongue; and a swelling fixed to skin (like a sebaceous cyst) moves with the skin and has a punctum. Eliciting the right movement for the site turns a vague lump into a specific diagnosis.
DISTINGUISHING CYSTIC FROM SOLID
A core aim of palpation is deciding whether a swelling is cystic (fluid-filled) or solid, because this reshapes the differential. A cystic swelling shows fluctuation, may transilluminate, and may have a fluid thrill; a solid swelling does none of these. Fluctuation is tested by pressing at two points and feeling the bulge transmitted in two perpendicular directions. Transillumination (shining a light through the swelling in a darkened room) confirms clear fluid — positive in a hydrocele or cystic hygroma but negative in a solid tumour or blood-filled swelling.
ASSESSING FOR MALIGNANCY
When a swelling might be malignant, the examination extends beyond the lump itself. Features suggesting malignancy include a hard, irregular, poorly-defined mass that is fixed to skin or deeper structures and possibly non-tender. The examination must then always include the regional lymph nodes (for metastatic spread) and a general survey for hepatomegaly and other masses. This is why 'examine the draining lymph nodes' is an inseparable part of assessing any significant swelling.
A NOTE ON PERCUSSION & SPECIAL TESTS
Beyond inspection and palpation, the examination is completed by percussion and special manoeuvres where relevant: a resonant percussion note over a swelling suggests gas-containing bowel (as in a hernia), while a dull note suggests solid or fluid content. Special tests are chosen for the site — a cough impulse and reducibility for a hernia, Buerger's test for a limb, and eliciting movement on swallowing or tongue protrusion for a neck lump. Selecting the right special test for the region is what converts a routine description into a diagnosis, and rounds off a complete, systematic examination.
💊KEY POINTS / NUMBERS (viva)- Sequence: history → inspection → palpation → percussion/auscultation → regional lymph nodes.
- Palpate: site, size, shape, surface, edge, consistency, temperature, tenderness, fluctuation, transillumination, pulsatility, mobility, plane.
- Fluctuation + transillumination = cystic; pulsatile + expansile = aneurysm; always examine regional nodes.
🔑KEY POINTS TO REMEMBER- Examine a swelling systematically: history, inspection, palpation, auscultation, then regional lymph nodes.
- Inspect: site, size, shape, surface, colour, overlying skin, movement (swallowing/tongue/respiration).
- Palpate: consistency, temperature, tenderness, edge, fluctuation, transillumination, pulsatility, compressibility, mobility, plane, cough impulse.
- Determine the plane: skin (moves with skin), subcutaneous (free), intramuscular (fixes on muscle contraction), bone (fixed).
- Fluctuation + transillumination = cystic; pulsatile + expansile = aneurysm; always assess regional nodes.
📚SOURCES: Bailey & Love's Short Practice of Surgery; SRB's Manual of Surgery.THE CONCEPT
Soft tissue sarcomas are malignant tumours arising from the mesenchymal (connective) tissues — fat, muscle, fibrous tissue, blood vessels and nerves. They are rare, and they behave quite differently from the common epithelial cancers (carcinomas): they tend to spread by the bloodstream to the lungs rather than to lymph nodes, and they require specialised management to avoid disastrous outcomes from inappropriate surgery. The overriding message is that a soft tissue lump with worrying features must be referred to a specialist before it is touched.
TYPES & RISK FACTORS
There are many histological types named after their tissue of origin — liposarcoma (fat), leiomyosarcoma (smooth muscle), rhabdomyosarcoma (skeletal muscle), fibrosarcoma, synovial sarcoma, angiosarcoma, and the gastrointestinal stromal tumour (GIST). Most are sporadic; recognised risk factors include previous radiotherapy, genetic syndromes (neurofibromatosis, Li-Fraumeni), and chronic lymphoedema (angiosarcoma).
CLINICAL FEATURES — THE RED FLAGS
A sarcoma typically presents as a painless, enlarging, deep soft tissue mass, most often in the thigh or limb. The crucial clinical rule is that a soft tissue lump that is large (> 5 cm), deep to the fascia, growing, or painful should be regarded as a sarcoma until proven otherwise — features that should trigger urgent specialist referral rather than casual excision.
SPREAD
Unlike carcinomas, soft tissue sarcomas spread haematogenously — characteristically to the lungs — and only rarely to lymph nodes. They are also locally infiltrative, extending along tissue planes beyond their apparent capsule, which has important surgical implications.
INVESTIGATION & MANAGEMENT — THE GOLDEN RULES
Assessment is by MRI of the primary (the best imaging of soft tissue), a CT of the chest (for lung metastases), and a core-needle biopsy. Two golden rules govern management:
- The lesion must be referred to a specialist sarcoma centre before biopsy, and the biopsy planned so its track can be excised later — a poorly-placed biopsy contaminates tissue planes and compromises curative surgery.
- The tumour must never be simply 'shelled out' (enucleated), because its infiltrative edge means this leaves disease behind and causes recurrence.
Definitive treatment is wide local excision with clear margins, usually combined with radiotherapy; chemotherapy has a role in certain types, and lung metastases may be resected.
💡CLINICAL PEARL: The single most important teaching point: a soft tissue lump that is > 5 cm, deep, growing or painful is a sarcoma until proven otherwise — refer to a sarcoma centre, image with MRI and take a planned core biopsy; do NOT excise or 'shell it out'. Remember it spreads to the lung (haematogenous), not to lymph nodes.WHY THE 'PSEUDOCAPSULE' IS DANGEROUS
A key concept explaining the surgical rules is the sarcoma's pseudocapsule. As the tumour grows it compresses surrounding tissue into a false 'capsule' that looks like a clean plane but actually contains infiltrating tumour cells (satellite nodules) extending beyond it. This is precisely why 'shelling out' the tumour along this plane leaves microscopic disease behind and leads to local recurrence. Proper treatment removes a cuff of normal tissue all around (wide excision), not just the visible mass — a principle that distinguishes sarcoma surgery from benign lump removal.
GRADING & STAGING
Sarcomas are assessed by histological grade (how aggressive the cells look) and stage, and grade is one of the strongest predictors of behaviour — high-grade sarcomas are more likely to metastasise. Because their main route of spread is to the lungs, a CT of the chest is essential for staging, and follow-up includes lung surveillance. This focus on the chest (rather than on lymph nodes, as for carcinomas) reflects the fundamentally different biology of these mesenchymal cancers.
A NOTE ON GIST
The gastrointestinal stromal tumour (GIST) is a distinctive sarcoma worth knowing: it arises from the interstitial cells of Cajal in the gut wall (commonly the stomach), typically carries a mutation in the c-KIT gene, and — uniquely among sarcomas — responds to the targeted tyrosine kinase inhibitor imatinib. This makes GIST an important example of how molecular understanding has produced an effective drug therapy for a tumour that is otherwise treated surgically.
A NOTE ON THE MULTIDISCIPLINARY APPROACH
Because sarcomas are rare and their correct handling is so specialised, their management is centralised in specialist sarcoma centres with a multidisciplinary team — surgeons, oncologists, radiologists and pathologists — who plan the biopsy, imaging and treatment together. This concentration of expertise matters because the first treatment offers the best chance of cure: an inappropriate 'lump excision' by a non-specialist contaminates tissue planes, worsens local control and can cost the patient a limb. The recurring message of the whole topic is therefore 'suspect it, don't touch it, and refer it'.
💊KEY POINTS / NUMBERS (viva)- Red flags for sarcoma: soft tissue lump >5 cm, deep to fascia, growing, or painful → refer to a sarcoma centre.
- Investigate with MRI (primary) + CT chest (lung mets) + planned core-needle biopsy (never simple excision/'shelling out').
- Spreads haematogenously to the LUNG (rarely to nodes); treat by wide excision + radiotherapy.
🔑KEY POINTS TO REMEMBER- Soft tissue sarcomas = rare malignant tumours of mesenchymal tissue (fat, muscle, fibrous, vessel, nerve).
- Red flags: painless deep soft tissue mass >5 cm, growing or painful = sarcoma until proven otherwise.
- Spread haematogenously to the LUNG (rarely nodes); locally infiltrative beyond the apparent capsule.
- Refer to a specialist sarcoma centre BEFORE biopsy; MRI + CT chest + planned core biopsy; never 'shell out'/excise blindly.
- Treat by wide local excision with clear margins + radiotherapy (± chemotherapy); resect lung metastases where feasible.
📚SOURCES: Bailey & Love's Short Practice of Surgery; SRB's Manual of Surgery.THE CONCEPT
An ulcer is a break in the continuity of the covering epithelium (skin or mucous membrane). Ulcers are common surgical problems, and the whole subject becomes manageable if approached in two steps: classifying the ulcer by its cause, and examining it systematically — with the edge of the ulcer often revealing the diagnosis.
CLASSIFICATION BY CAUSE
- Venous (gravitational) — in the gaiter area, from chronic venous insufficiency.
- Arterial (ischaemic) — painful, punched-out, over pressure points/toes, from PAD.
- Neuropathic (trophic) — painless, over pressure points, in diabetes, leprosy or nerve injury.
- Malignant — SCC, BCC or melanoma; and Marjolin's ulcer (malignancy in a chronic scar/ulcer).
- Infective — tuberculous, syphilitic; and traumatic and pressure (decubitus) sores.
PARTS OF AN ULCER
An ulcer is described in terms of its margin, edge, floor (the exposed surface), base (the tissue on which it rests), discharge, and the surrounding skin.
THE EDGE — A KEY DIAGNOSTIC CLUE
Edge Suggests Sloping Healing ulcer / venous ulcer Punched-out Arterial (ischaemic) or neuropathic (trophic) Undermined Tuberculous (also pressure sore) Rolled/raised & beaded Basal cell carcinoma (rodent ulcer) Everted Squamous cell carcinoma / malignant EXAMINATION & INVESTIGATION
Examination records the site, size, shape, edge, floor, base, discharge, tenderness, surrounding skin, sensation and regional nodes, along with the peripheral pulses (arterial disease). Investigations include a swab (infection), ABPI (to distinguish and manage arterial vs venous ulcers), blood glucose, and — importantly — a biopsy of the edge of any chronic or suspicious ulcer to exclude malignancy.
MANAGEMENT
Management is to treat the underlying cause (compression for venous ulcers, revascularisation for arterial ulcers, foot care and glycaemic control for diabetic ulcers), provide appropriate wound care and dressings, treat infection, and consider skin grafting for large clean ulcers. Any suspicious ulcer is biopsied.
💡CLINICAL PEARL: The examiner's favourite: the edge tells the cause — sloping (healing/venous), punched-out (arterial/neuropathic), undermined (tuberculous), rolled and beaded (BCC), everted (SCC). And the safety rule: biopsy the edge of any chronic, non-healing or changing ulcer to exclude malignancy (Marjolin's ulcer).THE PATHOPHYSIOLOGY OF THE VENOUS ULCER
Because venous ulcers are so common, understanding their mechanism is worthwhile. Sustained venous hypertension (from valvular incompetence or previous DVT) is transmitted to the skin capillaries of the lower leg, causing leakage of fluid, fibrinogen and red cells into the tissues. This produces the surrounding skin changes — haemosiderin pigmentation, lipodermatosclerosis and eczema — and impairs oxygen delivery, so that minor injury in the vulnerable gaiter area breaks down into a chronic ulcer. This is why the treatment (graduated compression) is aimed at reversing the venous hypertension rather than at the ulcer surface alone.
THE NEUROPATHIC (TROPHIC) ULCER
The neuropathic (trophic) ulcer illustrates a different mechanism: loss of protective sensation (in diabetes, leprosy or nerve injury) means repeated pressure and minor trauma go unfelt and unheeded, so tissue breaks down painlessly over pressure-bearing points (the sole, heel, metatarsal heads). Because the ulcer is painless, patients present late. Management centres on offloading pressure, meticulous foot care, and treating the underlying cause — the pain-free nature being both the diagnostic clue and the reason for delayed presentation.
HEALING & GENERAL PRINCIPLES
Whatever the cause, an ulcer will only heal if the local and general conditions for healing are met: adequate blood supply (hence checking pulses/ABPI), control of infection, relief of the underlying cause (pressure, venous hypertension, ischaemia), and good general/nutritional status and glycaemic control. A clean, granulating ulcer with a good blood supply may be closed more quickly with a skin graft. Framing ulcer care around 'remove the cause and optimise healing' ties the whole topic together.
A NOTE ON THE TUBERCULOUS ULCER
The tuberculous ulcer illustrates why the edge is such a useful sign: it characteristically has a bluish, undermined edge (the disease burrows beneath the skin faster than the surface breaks down), with a floor of pale granulation tissue and 'wash-leather' slough. It is typically found overlying a tuberculous lymph node or joint. Recognising the undermined edge, together with the clinical context, points to an infective (tuberculous) cause and directs investigation towards biopsy, culture and anti-tuberculous treatment rather than simple wound care.
💊KEY POINTS / NUMBERS (viva)- Edge: sloping (healing/venous), punched-out (arterial/neuropathic), undermined (TB), rolled/beaded (BCC), everted (SCC).
- Investigate: swab, ABPI (arterial vs venous), blood glucose, and biopsy of the edge (exclude malignancy).
- Treat the cause: compression (venous), revascularisation (arterial), foot care/glycaemic control (diabetic).
🔑KEY POINTS TO REMEMBER- Ulcer = break in the covering epithelium; classify by cause: venous, arterial, neuropathic, malignant, infective (TB), traumatic, pressure.
- Describe: margin, edge, floor, base, discharge, surrounding skin.
- Edge tells the cause: sloping (healing/venous), punched-out (arterial/neuropathic), undermined (TB), rolled/beaded (BCC), everted (SCC).
- Examine + ABPI, blood glucose, swab; BIOPSY the edge of any chronic/suspicious ulcer (exclude malignancy — Marjolin's).
- Treat the underlying cause (compression/revascularise/foot care) + wound care ± skin grafting.
📚SOURCES: Bailey & Love's Short Practice of Surgery; SRB's Manual of Surgery.THE CONCEPT
A lipoma is a benign tumour of mature fat cells (adipocytes), and it is the commonest benign soft-tissue tumour. Because fat is present almost everywhere in the body, a lipoma can occur at almost any site — earning it the nickname the 'universal tumour' — though it is most often found in the subcutaneous tissue.
CLINICAL FEATURES
A lipoma is characteristically a soft, lobulated, well-defined, mobile, painless swelling. Two signs are useful: it has a 'slip sign' (the edge slips away from the examining finger, because it is soft and encapsulated), and it may feel pseudo-fluctuant. Most are solitary; multiple painful lipomas occur in Dercum's disease (adiposis dolorosa).
MANAGEMENT & THE IMPORTANT CAVEAT
A small, typical lipoma can be reassured and observed; excision is done for large or symptomatic lesions, cosmetic reasons, or diagnostic doubt. The important caveat is that a lump which is large (> 5 cm), deep, rapidly growing or painful may be a liposarcoma rather than a benign lipoma, and warrants imaging and specialist assessment rather than simple excision.
PLANE & DIAGNOSIS
On examination a lipoma sits in the subcutaneous plane — it is free from the overlying skin (no punctum, unlike a sebaceous cyst) and mobile over deeper structures — which, with its soft lobulated feel and slip sign, usually makes the diagnosis clinical. Most subcutaneous lipomas need no investigation. It is the deep or unusually large lump where imaging (ultrasound or MRI) is used, precisely to distinguish a benign lipoma from a liposarcoma before deciding on treatment.
THE BOTTOM LINE
A lipoma is a benign, soft, mobile subcutaneous tumour of fat with a slip sign, usually diagnosed clinically and simply observed or excised — but a large, deep or growing 'lipoma' must be imaged to exclude a liposarcoma.
A NOTE ON VARIANTS & SITES
Lipomas have several recognised variants and sites worth a mention: an angiolipoma (containing blood vessels) can be tender; a subfascial or intramuscular lipoma lies deep and is harder to assess clinically; and lipomas occur at classic sites such as the neck, shoulders, back and limbs. Most remain small and stable for years. The practical rule stays the same — a benign-feeling, stable, superficial lipoma is reassured or excised for symptoms, while any deep, large or changing fatty lump prompts imaging to exclude malignancy.
🔑KEY POINTS TO REMEMBER- Lipoma = benign tumour of mature fat cells; commonest benign soft-tissue tumour ('universal tumour').
- Soft, lobulated, well-defined, mobile, painless; positive 'slip sign'; pseudo-fluctuant.
- Multiple painful lipomas = Dercum's disease (adiposis dolorosa).
- Reassure/observe or excise if large/symptomatic/doubtful; beware liposarcoma (large, deep, growing, painful) → image and refer.
📚SOURCES: Bailey & Love's Short Practice of Surgery.THE CONCEPT
A 'sebaceous cyst' is a common skin cyst arising from a blocked pilosebaceous (hair follicle) unit, filled with keratin. The name is something of a misnomer — the contents are mostly keratin (epidermoid or pilar cyst), not sebum — but the term is entrenched. It occurs on hair-bearing skin, commonly the scalp, face, neck and scrotum.
CLINICAL FEATURES — THE PUNCTUM
It presents as a firm, round, smooth swelling within the skin that moves with the skin (confirming its cutaneous plane). Its pathognomonic feature is a central punctum — a small dark dot on the surface marking the blocked follicular opening. The contents are a cheesy, keratinous, often foul-smelling material.
COMPLICATIONS & MANAGEMENT
Complications include infection (a red, painful, discharging cyst), ulceration, a sebaceous horn, and (rarely) an ulcerating proliferative form called Cock's peculiar tumour. Treatment is complete surgical excision, removing the entire cyst wall — because leaving any of the lining leads to recurrence. An infected cyst is usually treated (incision/drainage and antibiotics) before definitive excision when the inflammation has settled.
SEBACEOUS CYST VS LIPOMA
A common exam contrast is the sebaceous cyst versus the lipoma. The sebaceous cyst is in the skin (moves with the skin, has a central punctum, contains cheesy keratin), whereas the lipoma is subcutaneous (skin moves freely over it, no punctum, soft and lobulated with a slip sign). This distinction of plane and the presence or absence of a punctum is usually enough to tell them apart clinically, and it is a favourite bedside question.
THE BOTTOM LINE
A sebaceous cyst is a keratin-filled cutaneous cyst with a central punctum that moves with the skin, treated by complete excision of the cyst wall to prevent recurrence.
A NOTE ON MANAGING THE INFECTED CYST
The management of an infected sebaceous cyst follows a logical sequence: while acutely inflamed and infected, the cyst is treated with antibiotics and, if it has formed an abscess, incision and drainage — but definitive excision is deferred until the inflammation settles, because attempting to remove the whole wall in the middle of acute infection is difficult and tends to leave fragments behind. Once quiet, the cyst is excised completely with its wall to prevent recurrence — a sequence that mirrors the general surgical principle of not doing definitive surgery in infected, inflamed tissue.
🔑KEY POINTS TO REMEMBER- 'Sebaceous cyst' = keratin-filled cyst from a blocked pilosebaceous unit (mostly epidermoid/keratin, not sebum); scalp, face, neck, scrotum.
- Firm, round swelling in the skin, moving with the skin, with a pathognomonic central PUNCTUM; cheesy keratinous contents.
- Complications: infection, discharge, sebaceous horn, Cock's peculiar tumour.
- Treat by complete excision of the whole cyst wall (to prevent recurrence); settle infection first if present.
📚SOURCES: Bailey & Love's Short Practice of Surgery.THE CONCEPT
A dermoid cyst is a cyst lined by squamous epithelium and containing skin appendages (such as hair follicles and sebaceous glands) within its wall — hence 'dermoid' (skin-like). There are two mechanisms of formation, congenital and acquired, which determine where these cysts are found.
CONGENITAL (SEQUESTRATION) DERMOID
A congenital (sequestration) dermoid forms when epithelial cells are trapped along the lines of embryonic fusion during development. They therefore occur at characteristic sites where skin folds fuse — for example the external angular dermoid at the outer angle of the eyebrow, the midline of the neck, and the root of the nose.
ACQUIRED (IMPLANTATION) DERMOID & MANAGEMENT
An acquired (implantation) dermoid results when trauma drives a fragment of skin epithelium into the deeper tissues, where it forms a cyst — classically on the fingers of people whose work involves repeated minor trauma. A dermoid cyst is a smooth, soft, cystic swelling; treatment is complete surgical excision (with imaging first for a midline lesion that might have deep/intracranial extension).
A NOTE ON MIDLINE DERMOIDS
A practical caution concerns midline dermoid cysts (such as those at the root of the nose or in the midline of the scalp/neck): these can have a deep extension, occasionally communicating intracranially. For this reason a midline dermoid should be imaged (CT/MRI) before excision to define any deep tract, so that surgery is planned safely rather than an unexpected deep connection being encountered during removal.
THE BOTTOM LINE
A dermoid cyst is a squamous-lined cyst containing skin appendages — congenital along fusion lines (external angular, midline) or acquired by implantation (fingers) — treated by excision, imaging midline lesions first.
A NOTE ON HISTOLOGY & THE CONTRAST WITH TERATOMA
Histologically a dermoid cyst is lined by keratinising squamous epithelium with dermal appendages (hair follicles, sebaceous and sweat glands) in its wall, and may contain hair and sebaceous material. It should be distinguished from the ovarian (cystic) teratoma, which is also colloquially called a 'dermoid' but is a true germ-cell tumour containing tissues from all three germ layers. The surgical dermoids discussed here are the simple congenital and implantation cysts of the skin and subcutaneous tissue.
🔑KEY POINTS TO REMEMBER- Dermoid cyst = cyst lined by squamous epithelium containing skin appendages (hair, sebaceous glands).
- Congenital (sequestration): epithelium trapped along embryonic fusion lines — external angular dermoid (eyebrow), midline neck, root of nose.
- Acquired (implantation): trauma drives epithelium into deeper tissue — classically the fingers.
- Smooth, soft, cystic swelling; treat by complete excision (image midline lesions for deep extension first).
📚SOURCES: Bailey & Love's Short Practice of Surgery.THE CONCEPT
A ganglion is a cystic swelling arising from a joint capsule or a tendon sheath, containing clear, gelatinous, mucoid fluid. It is one of the commonest soft-tissue swellings, and its typical and diagnostic location is the dorsum of the wrist (also the volar wrist, dorsum of the foot and around the fingers). Its connection to the underlying synovial structure is central to its identity.
CLINICAL FEATURES
A ganglion is a smooth, well-defined, rounded swelling that is often tense (and may therefore feel firm or even hard rather than obviously cystic); because it contains clear fluid it may transilluminate. It is usually painless (though it can ache), and is characteristically tethered to the deeper joint or tendon sheath from which it arises (so it moves little, and may become more prominent on flexing the joint).
MANAGEMENT
Because many ganglia are harmless and some resolve spontaneously, simple reassurance is often sufficient. Symptomatic ganglia can be treated by aspiration (though recurrence is common) or surgical excision; even after excision, recurrence can occur if the connection to the joint/sheath is not fully dealt with. (The old remedy of striking it with a heavy book is no longer recommended.)
A NOTE ON THE COMPOUND PALMAR GANGLION
A specific variant worth knowing is the compound palmar ganglion — a swelling of the common flexor tendon sheath at the wrist, crossing the flexor retinaculum so that it bulges both above and below it, sometimes with a 'cross-fluctuation' sign (pressure on one part transmits to the other). It is classically associated with tuberculous tenosynovitis and may contain fibrin bodies ('melon-seed bodies'). This links the everyday ganglion to an important infective cause.
THE BOTTOM LINE
A ganglion is a mucoid-filled cystic swelling from a joint capsule or tendon sheath, commonest at the dorsum of the wrist, often resolving spontaneously but treated by excision if symptomatic.
A NOTE ON TRANSILLUMINATION & CONSISTENCY
A point that often causes confusion is that a ganglion, despite being a fluid-filled cyst, is frequently so tense that it feels firm or even bony-hard rather than obviously cystic, and fluctuation can be difficult to elicit. Its clear mucoid contents do allow transillumination, and its fixed relationship to the underlying joint or tendon sheath — becoming tenser when the joint is put into certain positions — helps confirm the diagnosis. Appreciating this prevents a tense ganglion being mistaken for a solid tumour.
🔑KEY POINTS TO REMEMBER- Ganglion = cystic swelling from a joint capsule or tendon sheath containing clear gelatinous/mucoid fluid; commonest on the dorsum of the wrist.
- Smooth, well-defined, often tense (may feel firm/hard), may transilluminate, usually painless, tethered to the deeper joint/sheath.
- Many resolve spontaneously → reassurance; aspiration (recurs) or surgical excision if symptomatic (recurrence possible).
📚SOURCES: Bailey & Love's Short Practice of Surgery.THE CONCEPT
A neurofibroma is a benign tumour of the nerve sheath (composed of Schwann cells and fibroblasts). Solitary neurofibromas are common and harmless, but their importance is amplified when they occur as part of the inherited syndrome neurofibromatosis, in which multiple lesions and other systemic features occur.
NEUROFIBROMATOSIS TYPE 1 (VON RECKLINGHAUSEN'S)
NF1 is an autosomal dominant condition characterised by multiple cutaneous neurofibromas, café-au-lait macules (six or more), axillary and inguinal freckling, Lisch nodules (iris hamartomas), and optic gliomas. Complications include large plexiform neurofibromas, skeletal abnormalities (e.g. scoliosis), and — importantly — malignant transformation to a malignant peripheral nerve sheath tumour (MPNST), suggested by rapid growth or pain in a pre-existing lesion.
NF2 & MANAGEMENT
NF2 is a distinct disorder characterised by bilateral acoustic neuromas (vestibular schwannomas), presenting with hearing loss. Management of neurofibromatosis is largely surveillance and excision of symptomatic, disfiguring or suspicious lesions (with prompt biopsy/excision of any lesion suggesting malignant change), together with genetic counselling and monitoring for the syndromic complications.
A NOTE ON DIAGNOSTIC CRITERIA
NF1 is diagnosed on recognised clinical criteria, of which two or more are required — these include six or more café-au-lait spots, two or more neurofibromas (or one plexiform), axillary/inguinal freckling, an optic glioma, two or more Lisch nodules, a characteristic bony lesion, and a first-degree relative with NF1. Knowing that the diagnosis is a constellation of features (not a single lesion) explains why examination looks systematically for skin, eye, skeletal and family findings.
THE BOTTOM LINE
A neurofibroma is a benign nerve-sheath tumour; multiple lesions with café-au-lait spots and freckling indicate NF1 (von Recklinghausen's), which carries a risk of malignant transformation (MPNST) and needs surveillance.
A NOTE ON WARNING SIGNS OF MALIGNANCY
In a patient with neurofibromatosis, certain changes in a pre-existing neurofibroma are warning signs of malignant transformation to an MPNST and must not be ignored: rapid increase in size, new or increasing pain, and neurological deficit arising from a previously stable lesion. Such a lesion needs urgent imaging and biopsy, because MPNST is aggressive and its prognosis depends on early, complete excision. This vigilance for change is a key part of the long-term surveillance of NF1 patients.
🔑KEY POINTS TO REMEMBER- Neurofibroma = benign nerve-sheath tumour (Schwann cells + fibroblasts); may be solitary or part of neurofibromatosis.
- NF1 (von Recklinghausen's): autosomal dominant — multiple neurofibromas, café-au-lait spots (≥6), axillary/inguinal freckling, Lisch nodules, optic glioma.
- Complications: plexiform neurofibroma, skeletal changes, malignant transformation (MPNST — rapid growth/pain).
- NF2: bilateral acoustic neuromas (vestibular schwannomas).
- Manage by surveillance + excision of symptomatic/suspicious lesions; genetic counselling.
📚SOURCES: Bailey & Love's Short Practice of Surgery.THE CONCEPT
A Marjolin's ulcer is a squamous cell carcinoma that arises in a chronic wound, scar or long-standing ulcer — for example an old burn scar, a chronic venous ulcer, a chronic sinus, or an area of chronic osteomyelitis. It is an important concept because it means a chronic, apparently benign wound can undergo malignant change, and the key clinical skill is to recognise this transformation.
CHARACTERISTIC FEATURES
A Marjolin's ulcer has several distinctive features that follow from arising in scar tissue: it tends to be slow-growing (the scar has few lymphatics, so lymphatic spread is slow) and is painless (scar tissue is relatively insensate). Signs of malignant change in a chronic ulcer include a raised, everted edge, increased or heaped-up growth, bleeding, and a change in the appearance of a previously stable wound.
DIAGNOSIS & MANAGEMENT
The diagnosis is confirmed by biopsy of the ulcer edge — reinforcing the general rule that any chronic, non-healing or changing ulcer should be biopsied to exclude malignancy. Treatment is wide surgical excision (with management of lymph nodes if involved). Once it does spread to nodes, the prognosis worsens.
💡CLINICAL PEARL: The rule to state: any chronic ulcer or scar that changes — develops a raised/everted edge, starts growing, or bleeds — must be biopsied to exclude a Marjolin's ulcer (SCC). Long-standing burn scars and chronic venous ulcers are the classic sites.A NOTE ON THE MECHANISM
The mechanism of malignant change is thought to involve chronic inflammation, repeated cycles of ulceration and healing, and long-standing epithelial instability in the scar or wound, eventually giving rise to squamous carcinoma — often after many years or decades. This long latency is why a burn scar that ulcerates years later, or a venous ulcer of very long standing that changes character, must always raise the suspicion of a Marjolin's ulcer and prompt a biopsy.
THE BOTTOM LINE
A Marjolin's ulcer is a squamous cell carcinoma arising in a chronic scar or ulcer — slow-growing and painless — so any chronic or changing wound must be biopsied to exclude it and treated by wide excision.
A NOTE ON PROGNOSIS & NODAL SPREAD
Although a Marjolin's ulcer is often described as slow-growing while confined to the scar (which has few lymphatics), this apparent indolence is deceptive: once the tumour grows beyond the scar into normal tissue with intact lymphatics, it can spread to regional lymph nodes, and at that point the prognosis becomes significantly worse. This is a further argument for early biopsy and wide excision before nodal spread occurs, and for examining and, if necessary, treating the draining lymph nodes.
🔑KEY POINTS TO REMEMBER- Marjolin's ulcer = squamous cell carcinoma arising in a chronic wound/scar/ulcer (old burn scar, chronic venous ulcer, sinus, osteomyelitis).
- Slow-growing (few lymphatics in scar) and painless (insensate scar); malignant change shown by a raised/everted edge, heaped growth, bleeding.
- Biopsy the ulcer edge — any chronic/changing ulcer must be biopsied to exclude malignancy.
- Treat by wide surgical excision (± node management).
📚SOURCES: Bailey & Love's Short Practice of Surgery.THE CONCEPT
A biopsy is the removal of tissue for histological (or cytological) examination to establish a diagnosis. Choosing the right type of biopsy — and performing it correctly — is a fundamental surgical principle, because the biopsy must give a reliable diagnosis without compromising subsequent definitive treatment.
TYPES OF BIOPSY
- Fine-needle aspiration cytology (FNAC) — aspiration of cells for cytology (e.g. thyroid nodule, breast lump, lymph node); quick and simple, but shows cells only, not tissue architecture.
- Core-needle biopsy — a core of tissue that preserves architecture, allowing a fuller histological diagnosis (e.g. breast, prostate, sarcoma).
- Incisional biopsy — removal of a portion of a large lesion for diagnosis before planning treatment.
- Excisional biopsy — removal of the whole lesion (both diagnostic and therapeutic for small lesions, e.g. a suspicious mole/melanoma, or a lymph node for suspected lymphoma).
PRINCIPLES OF A GOOD BIOPSY
A biopsy should obtain an adequate, representative sample — typically taken from the edge of a lesion to include both normal and abnormal tissue, avoiding the necrotic centre. Crucially, the biopsy must not compromise definitive surgery: the biopsy track should be placed so it can be excised with the tumour (especially vital for soft tissue sarcoma and melanoma, where a badly-placed biopsy contaminates tissue planes). The sample is sent for histopathology (fixed in formalin), with fresh tissue where special studies are needed.
FNAC VS CORE BIOPSY
A frequently-asked contrast is FNAC versus core biopsy. FNAC samples only cells — it is quick, cheap and good for confirming a node or a thyroid/breast lesion, but it cannot show tissue architecture, so it cannot always distinguish, for example, invasive from in-situ cancer. A core biopsy yields an intact tissue core that preserves architecture, allowing grading and receptor studies. Choosing between them depends on how much information the diagnosis and treatment plan require.
THE BOTTOM LINE
A biopsy establishes a tissue diagnosis by the least invasive adequate means (FNAC, core, incisional or excisional) while ensuring the biopsy track can be excised with any tumour, so definitive surgery is never compromised.
A NOTE ON FROZEN SECTION
A useful special technique is the frozen section — rapid histological examination of tissue during an operation, giving a provisional diagnosis within minutes. It is used to confirm malignancy, check whether a resection margin is clear, or assess a lymph node while the patient is still anaesthetised, so the surgeon can decide the extent of surgery there and then. Its limitation is that it is less detailed than standard paraffin histology, so definitive typing still awaits the full report.
🔑KEY POINTS TO REMEMBER- Biopsy = removal of tissue for histological/cytological diagnosis without compromising definitive treatment.
- FNAC (cells/cytology), core biopsy (tissue architecture), incisional (part of a large lesion), excisional (whole lesion — e.g. melanoma, lymph node).
- Take an adequate, representative sample from the edge (include normal + abnormal), avoiding necrotic centre.
- Place the biopsy track so it can be excised with the tumour (crucial for sarcoma and melanoma); send for histopathology.
📚SOURCES: Bailey & Love's Short Practice of Surgery.