Chronic ovarian pregnancy mimicking an ovarian tumor diagnosed by peritoneal washing cytology: a case report

BACKGROUND: Chronic ectopic pregnancy is an enigma. The clinical presentation can be mild, with absent or subtle symptoms. Ovarian pregnancy usually ends with rupture. We report the first case of unruptured chronic ovarian pregnancy that was initially diagnosed by peritoneal washing cytology. CASE: A 35-year-old woman suffered from low abdominal pain during the presumed menstrual period for 6 months. Abdominal computed tomography revealed a huge cystic mass with intralesional hematoma and soft tissue components located in the pelvic cavity. Mild right hydronephrosis caused by tumor obstruction of the right ureter were noted. Right ovarian cancer was suspected. Peritoneal washing cytology revealed both cytotrophoblasts and syncytiotrophoblasts. Patient received enucleation of the right ovary. Microscopically, the ovarian mass exhibited extensive hemorrhage and necrosis, embedding degenerated chorionic villi. CONCLUSION: When a patient experiences low abdominal pain during a menstrual period, the possibility of ectopic pregnancy should be considered in addition to possible endometriosis. Ovarian or other abdominal pregnancies, even untruptured, may be discriminated from other lesions in cases of abdominal pain by peritoneal washing cytology.