Describe the assessment of a thyroid swelling.

Thyroid Swellings

• A thyroid swelling (goitre) presents to the otolaryngologist because of its anatomical relations — the airway, the recurrent laryngeal nerves and the oesophagus.
• The assessment answers three questions: is it toxic, is it malignant, and is it compressing anything?
• A thyroid swelling moves on swallowing.
• It does not move on tongue protrusion, which separates it from a thyroglossal cyst
• Classification — diffuse (physiological, Graves disease, thyroiditis, iodine deficiency); multinodular; solitary nodule; and malignant
• Iodine deficiency remains a cause of endemic goitre in parts of India, particularly the sub-Himalayan belt, and universal salt iodisation has been the principal public health response
• The features suggesting malignancy — a hard, fixed nodule; rapid growth; hoarseness from recurrent laryngeal nerve involvement, which is highly suggestive; cervical lymphadenopathy; age under 20 or over 60; male sex; previous neck irradiation; and a family history of thyroid cancer or men syndrome
• Assessment — examine the gland and the whole neck; assess for retrosternal extension (the lower border not palpable, pemberton’S sign — facial congestion and stridor on raising the arms); and check for tracheal deviation
• Examine the vocal cords by nasendoscopy before any thyroid surgery, without exception — because a pre-existing palsy must be documented, both for surgical planning and for medicolegal protection, and because an asymptomatic palsy suggests malignancy
• Investigation — thyroid function tests first.
• FNAC, reported by the bethesda system.
• Radioisotope scanning only where there is thyrotoxicosis, to distinguish a hot (almost always benign) from a cold nodule
• CT or MRI for retrosternal extension and airway compression, and a calcitonin level where medullary carcinoma is suspected
• The thyroid malignancies, briefly — papillary, the commonest, in younger patients, spreading by lymphatics and with an excellent prognosis; follicular, spreading by blood to bone and lung, and diagnosed only on histology (capsular and vascular invasion), not on cytology, which is why FNAC reports a "follicular lesion" rather than a diagnosis; medullary, from parafollicular C cells, secreting calcitonin and associated with men 2; anaplastic, in the elderly, rapidly growing with airway obstruction and a very poor prognosis; and lymphoma, arising in a background of hashimoto thyroiditis
• Management — observation for benign asymptomatic disease; surgery for compression, retrosternal extension, cosmesis, toxicity or malignancy; and medical or radioiodine treatment for thyrotoxicosis