Histology, ultrastructure, and immunohistochemistry of strumal carcinoid: a case report.

A case of ovarian strumal carcinoid was studied by histochemistry, electron microscopy, and immunocytochemistry. The thyroid component of the tumor was micro-macrofollicular, whereas the carcinoid areas had a trabecular growth pattern. Carcinoid cells contained argyrophilic, dense-core secretory granules and were immunopositive for serotonin but not for calcitonin, somatostatin, or thyroglobulin. Follicular thyroid cells were positive for thyroglobulin, and were negative for calcitonin and somatostatin. Thyroglobulin and serotonin-containing cells were present in microfollicles adjacent to areas of trabecular carcinoid and struma ovarii. The data suggest that strumal carcinoids develop in close association with struma ovarii and represent a subset of ovarian teratomas. Current hypotheses on the cell of origin of strumal carcinoids are reviewed.