Thyroid Carcinoma: Pathological Types

Key points

• • Papillary carcinoma is the commonest thyroid cancer; it has ground-glass Orphan-Annie-eye nuclei and psammoma bodies, spreads by lymphatics, and has an excellent outlook.
• • Follicular carcinoma spreads through the blood rather than the lymphatics, and it is told apart from a benign follicular adenoma by invasion through its capsule or into vessels.
• • Medullary carcinoma arises from the calcitonin-secreting C cells (not follicular cells), contains amyloid in its stroma, and can be part of the inherited MEN 2 syndromes.
• • Anaplastic (undifferentiated) carcinoma occurs in older people, is highly aggressive with a very poor outlook, and can compress the airway and the food pipe in the neck.
• • Papillary and follicular cancers are the well-differentiated types and usually carry a good prognosis, especially in younger patients.
• • The type is confirmed by histopathological assessment; the characteristic nuclear features allow papillary carcinoma to be recognised even without the finger-like papillae.