[Ovarian carcinoid tumors: immunohistochemical and ultrastructural study of 8 cases].

Eight ovarian carcinoids, 4 trabecular and 4 strumal have been studied immunohistochemically for polypeptide hormones; three of them were also examined with the electron microscope. Seven of eight cases were positive for at least one polypeptide hormone. The trabecular parts of the 4 cases of strumal carcinoid were positive for pancreatic polypeptide. As the vesicular regions of these 4 cases were positive for thyroglobulin and for pancreatic polypeptide, we suspect the existence of "hybrid" thyroid and neuroendocrine cells. The electron microscopic examination revealed: the cell in the insular carcinoid had no distinct polarization and contained electron-dense granules of varying shape; in the trabecular part of the strumal carcinoid the cells were polarized and contained round electron-dense granules.