Primary peritoneal carcinomas of females: Clinicopathologic analysis and immunohistochemical study of 11 cases

Objective: To observe and analyze the clinicopathological features of primary peritoneal carcinoma in women. Methods: Eleven cases of primary peritoneal carcinoma in female patients were reviewed. The clinical and pathological records as well as all the available cytological and histological slides were reviewed. Immunohistochemical studies were performed in formalin fixed paraffin embedded tissue blocks of the peritoneal tumors. Results: The patients were postmenopausal females except one case. All the patients presented with abdominal distension. They were found to have ascites with positive cytology documented in ten cases. Laparotomy revealed multiple neoplastic nodules at the omentum and other peritoneal surfaces. Histologically, six were serous papillary adenocarcinoma, one was transitional cell carcinoma, and four were poorly differentiated serous adenocarcinoma with squamous cell carcinoma and/or transitional cell carcinoma components. Immunoreactivity for CK7 and EMA were demonstrated in all tumor tissues, 73% (8/11) of the tumors were positive for S 100 protein, while a few cases showed weak positivity for CEA, Calretinin and Vimentin. None of the cases were immunoreactive for CK 20. Conclusion: Primary peritoneal carcinomas of females are considered to arise from the secondary Mullerian system. They occur predominantly in postmenopausal women. The carcinomas may also display a wide variety of morphological appearances comparable to their ovarian counterparts. Immunohistochemical studies may be useful in distinguishing these tumors from metastasis from gastrointestinal tract and mesothelioma.