Strumal carcinoid of the ovary.

A 45-year-old woman presented with an apparently nonfunctioning strumal carcinoid of the ovary. On ultrastructural examination the cells in the solid parts of the tumor as well as in the "follicular" areas contained dense-core secretory granules, indicating that this neoplasm is a pure carcinoid tumor. The thyroid-like appearance in areas is due to the accumulation of secretory material within unusually dilated acinar spaces. This study raises the question whether any strumal carcinoid contains thyroid tissue since the cells forming the follicle-like spaces in this tumor contain dense-core granules.