Goblet-cell carcinoid tumor in peritoneal fluid: a case report.

An unusual case of goblet-cell carcinoid in the peritoneal fluid of a 49-yr-old woman with a prior history of carcinoid tumor of the appendix is presented and discussed. Cytologic findings included clusters of uniform small cells containing nuclei with finely granular chromatin, small prominent nucleoli, and scant cytoplasm admixed with signet-ring cells. Peritoneal biopsies contained acini and small glands lined by malignant cells with features of a carcinoid tumor. Prominent signet-ring cells were interspersed within tumor nests. The signet-ring cells and small glandular lumens showed strong mucin positivity. Endocrine tumor cells were argyrophil- and argentaffin-positive. The histologic findings confirmed the diagnosis of goblet-cell carcinoid involving peritoneal fluid.