Benign microfollicular adenoma: Findings on surgical histology

Surgical specimen of well-developed microfollicular adenoma. These lesions are benign if there is no evidence of either vascular or capsular invasion; the pathologic diagnosis is follicular cancer if invasion is seen.

Surgical specimen of a sporadic macrofollicular goiter with normal, large thyroid follicules filled with colloid. These follicles are disrupted by needle biopsy so that the colloid will smear across the slide or occassionally aggregate into droplets.