CA125-positive papillary tumor of the peritoneum

A 71-year-old female visited our outpatient unit with chief complaints of anorexia and a sense of abdominal distension. The abnormalities found after admission were conspicious increases in CA125 levels in serum and ascites as well as anemia, accelerated erythrocyte sedimentation and increased serum LDH. The patient underwent an emergency operation for ileus. The histological diagnosis was serous papillomatous cancer. Immunohistologic staining of the cancer tissue demonstrated the production of CA125. In this very rare the remnant of the Müllerian duct in the peritoneum is thought to have been cancerous.