Cytopathology of peritoneal endometriosis caused by ruptured ovarian cysts.

The cytopathologic features of two cases of peritoneal endometriosis (secondary to ruptured ovarian endometrial cysts) are described. Both patients presented with abdominal distension and tenderness and were clinically thought to have an abdominal tumor. Preoperative cytologic examination of peritoneal fluids gave a diagnosis of endometriosis in both cases. The endometrial tissue was present in the smears as honeycombs, syncytia and tight clusters of both epithelial and stromal cells. Subsequent surgery confirmed the cytodiagnosis in both cases. These cases emphasize the need to include endometriosis in the differential diagnosis of peritoneal effusions, especially in women.