Primary ovarian carcinoid with marked heterogeneity of microscopic features.

A primary ovarian carcinoid tumor in a 54-year-old patient with the carcinoid syndrome is reported. On histologic examination there were, in addition to typical insular and atypical ribbon-like areas, solid and papillary growth patterns with pleomorphic and clear cells, some with anaplastic features. The heterogeneity seen in this case has not been reported in an ovarian carcinoid. However, since argentaffine and some argyrophil granules were demonstrated by special stains and ultrastructural studies in all of the various cellular elements, it was concluded that the entire tumor represented a carcinoid. This case demonstrates that ovarian carcinoids are not necessarily insular, trabecular, or mixtures thereof, but can also be extremely heterogeneous. In order to identify more tumors of this kind and also to avoid a diagnosis of an anaplastic or unclassifiable carcinoma in such cases, it is recommended that special stains for neurosecretory granules and electron microscopic examination be carried out in a larger number of poorly differentiated ovarian neoplasms, especially in those in which some of the microscopic features are suggestive of a carcinoid.