Follicular adenoma

It is a benign neoplasm, presenting as a single nodule, usually not greater than 3 cm in diameter. Some of them can produce thyroid hormones and consequently cause hyperthyroidism (functioning or 'hot' adenomas). The hystologic pattern may vary: macrofollicular (composed of large follicles filled with colloid), microfollicular (with smaller follicles), trabecular (with follicular cells arranged in ribbons).

Classification (no prognostic significance)

• simple
• microfollicular
• trabecular
• oxyphil
• atypical
• papillary
• signet ring cell

Nodular hyperplasia	Follicular neoplasia
multiple	solitary
poorly encapsulated	encapsulated
architectural heterogeneity	uniformity of the architecture
cytologic heterogeneity	cytologic homogeneity
comparable areas in adjacent gland	different from surrounding gland
no compression of surrounding gland	compression of surrounding gland

 

Microfollicular groups		Microfollicular adenoma (histology)