Ectopic insulin production by a primary ovarian carcinoid.

An insulin-containing ovarian carcinoid was found at the autopsy of a 63-year-old woman with a 12-year history of episodic hyperinsulinemic hypoglycemia. In terms of histology, the carcinoid displayed both insular and trabecular patterns and contained a small focus of mucinous cystadenoma. Beta secretory granules were demonstrated by electron microscopy, and immunoreactivity for insulin was demonstrated in tumor cell cytoplasm by immunohistochemistry. Additional autopsy findings included a solitary parathyroid adenoma and a microscopic focus of pituitary hyperplasia. This is the first recorded case of insulin production by a primary ovarian neoplasm. The patient's constellation of endocrine findings may represent a variant of the syndrome of type I multiple endocrine neoplasia.