Q4 LONG ANSWER 10M ★ High-yield

Describe the tumours of the external ear.

ENT · 3rd Professional

Benign Tumours and Tumour-like Lesions

Tumours of the external ear are dominated by skin cancers of the pinna.

Lesion	Features
Exostoses	Multiple, bilateral, broad-based bony swellings of the deep bony canal, arising from periosteum. Associated with repeated exposure to cold water (surfer ear). asymptomatic; removed only if causing occlusion, wax retention or recurrent infection
Osteoma	Solitary, unilateral and peduncled, arising at a suture line. A true benign neoplasm
Keratosis obturans	A plug of desquamated keratin in a widened canal in younger patients, often bilateral and associated with bronchiectasis and sinusitis. Causes pain and conductive deafness
External canal cholesteatoma	Localised bony erosion with sequestration in an older patient, unilateral and painful. Distinct from keratosis obturans and needs surgery
Papilloma and seborrhoeic keratosis	Benign; excised for cosmesis or diagnosis
Ceruminoma (ceruminous gland tumours)	Arise from the ceruminous glands; include benign adenoma and the malignant adenoid cystic carcinoma.
Keloid	Common after ear piercing, particularly on the lobule and in darker skin; treated with intralesional steroid, excision with steroid or pressure, and radiotherapy in resistant cases
Chondrodermatitis nodularis helicis	A small, exquisitely painful nodule on the helix, worse on lying on that side. Benign, from pressure ischaemia of cartilage; mimics a carcinoma and is biopsied for that reason

Malignant Tumours

Malignancy OF the pinna — squamous cell carcinoma is the commonest on the pinna, unlike the face where basal cell carcinoma predominates, and arises on the helix in elderly men with chronic sun exposure. It metastasises to the parotid and cervical nodes
Basal cell carcinoma occurs more often on the postauricular and preauricular skin, and is locally invasive without metastasis
Melanoma is uncommon but carries a worse prognosis on the ear than elsewhere
Predisposing factors — chronic sun exposure, fair skin, actinic keratosis, chronic irritation, previous radiotherapy and immunosuppression
Malignancy OF the external canal is rare, and its importance lies entirely in the delay in diagnosis. It presents with pain, blood-stained discharge, granulations and a canal that fails to respond to treatment — that is, it is indistinguishable from chronic otitis externa or malignant otitis externa
The rule that follows IS the most important IN this answer: biopsy any granulation tissue or non-healing lesion in the canal, and biopsy any "otitis externa" that has not responded to adequate treatment. Delay is the reason these tumours present late and do badly
A long history of chronic suppurative otitis media is a recognised risk factor for carcinoma of the middle ear and canal, so a change in the character of the discharge to blood-stained, or the onset of pain in a previously painless discharging ear, demands biopsy
Spread is early and difficult to assess, into the parotid, temporomandibular joint, mastoid, facial nerve and skull base; facial palsy indicates advanced disease
Investigation — biopsy; high-resolution CT for bone and MRI for soft tissue and dural involvement; and assessment of the neck and parotid
Management — surgical excision with clear margins is the mainstay: wedge excision or partial pinnectomy for small pinna lesions, with reconstruction; and, for canal tumours, lateral or subtotal temporal bone resection with parotidectomy and neck dissection as indicated, followed by postoperative radiotherapy
Prognosis is good for small pinna lesions and poor for canal and temporal bone tumours, chiefly because of late presentation and the difficulty of clearing margins in that anatomy
Squamous carcinoma predominates on the pinna, unlike the face where basal cell carcinoma is commoner
Biopsy any granulation in the canal; carcinoma is indistinguishable from chronic otitis externa without histology
Blood-stained discharge in a chronic ear demands biopsy, as does the onset of pain in a previously painless discharging ear

Feature	Keratosis obturans	Canal cholesteatoma
Age	Younger adults	Older adults
Side	Usually bilateral	Usually unilateral
Pain	Acute and severe	Dull and chronic
Canal	Widened circumferentially, no erosion	Localised bony erosion with sequestrum
Hearing	Conductive loss common	Usually normal
Associations	Bronchiectasis and sinusitis	Trauma, previous surgery, radiotherapy
Treatment	Repeated removal of the keratin plug	Surgical debridement and canalplasty

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