Primary mucinous carcinoma of the thyroid gland: report of a case and ultrastructural study

A follicular carcinoma of the thyroid with extensive mucin production was found in a 54-year-old woman. The primary nature of this rare neoplasm of the thyroid gland is supposrted by the presence of both colloid and mucin-producing follicles. Ultrastructural features confirm the secretion of colloid and mucin in the same neoplastic thyroid cells.