Primary Peritoneal Serous Cancer: A Case Report of a Tumor in the Rectovaginal Septum

Peritoneal cancer is the invasion by malignant cells of serous membrane that lines the abdominal cavity, the viscera, and the coelom of the amniotes. Histologically, it is indistinguishable from ovarian counterpart, although in the former, it commonly involves the ovary only superficially, or it may totally lack an ovarian component, but with extensive involvement of the peritoneum, calcified perihepatic peritoneal nodules, or involvement of the omentum, in most cases. The current study describes the case of a 54-year-old female patient referring a history of colitis and dairy intolerance. A transvaginal ultrasound and a computed tomography (CT) scan revealed a tumor measuring 70×61×63 mm. CA-125 serum levels were 880 U/ml. Laparotomy surgery was indicated, and tumor was found at the level of the rectovaginal septum without evidence of metastasis. Tumor dissection and protective colostomy with loop sigmoid colon were performed. A pathological study gave a diagnosis of a high-grade peritoneal serous carcinoma with a micropapillary pattern. The present study describes the case of papillary serous peritoneal cancer presented as a single tumor mass without extensive involvement of the peritoneum. Additionally, the need for routine tests for its diagnosis and documenting hormonal alterations as the cause of its origin are suggested.