Primary peritoneal carcinoma presenting as adenocarcinoma on a Pap smear. A case report.

Background: Primary peritoneal carcinoma is an uncommon malignancy that usually presents with gastrointestinal symptoms from abdominal carcinomatosis.

Case: A postmenopausal woman presented with vaginal bleeding and adenocarcinoma cells on a Pap smear. Colposcopy, endocervical and endometrial curettage, mammography, colonoscopy and pelvic ultrasound were all normal. Computed tomography revealed a large omental cake and ascites, and the CA-125 level was elevated, 2,907 IU/mL. Exploratory laparotomy revealed a primary peritoneal carcinoma with abdominal carcinomatosis.

Conclusion: Primary peritoneal carcinoma should be considered in the differential diagnosis of adenocarcinoma cells arising on a Pap smear in the absence of cervical and endometrial cancer.