Strumal carcinoid of the ovary: ultrastructural observations and long-term follow-up study.

Herein is reported an ovarian strumal carcinoid in a mature tetratoma from a 54-year-old women. Ultrastructural examination revealed numerous electron-dense intracellular granules, which were intrepreted as neurosecretory granules. They corresponded to argyrophil granules observed by light microscopy and were identified within neoplastic cells arranged in both follicular and trabecular patterns. These findings corroborate the contention that the strumal carcinoid itself is a pure neuroendocrine tumor devoid of thyroid follicular epithelium, but do not disprove its possible origin from parafollicular cells of adjacent teratomatous thyroid tissue. There was no recurrence of tumor during the 20 1/2 years the patient was followed.