Primary peritoneal malignant mixed Mullerian tumors - A clinicopathologic,immunohistochemical, and genetic study

BACKGROUND. Primary peritoneal malignant mixed Mullerian tumors (MMMTs) are rarely reported in the literature. METHODS, The clinical, pathologic, and immunohistochemical features of five cases of MMMT of female peritoneum were analyzed. The tumors were also inv estigated for expression of hormone receptors, specific BRCA-1 mutations, a nd clonality. RESULTS. The patients' ages ranged from 33 to 67 years. They presented with abdominal pain or mass. One case of peritoneal MMMT was associated with a synchronous endometrial carcinoma whereas another case was detected 2 years after the diagnosis of a primary adenocarcinoma of the fallopian tube. One patient died 1 month after diagnosis whereas 2 patients died with disease within 1 year. Both carcinomatous and sarcomatous elements are present in a ll the tumors. Squamous differentiation was noted in two cases. Heterologou s elements, including chondroid, rhabodomyoblastic, and osteoid differentia tion were detected in all tumors. Immunohistochemical studies confirm the b iphasic differentiation with variable demonstration of neural and smooth mu scle differentiation. All five MMMTs were negative for estrogen and progest ogen receptors although the related endometrial and tubal carcinomas were p ositive. Heteroduplex analysis used to screen for specific BRCA-1 mutations were negative in all five MMMTs. Clonality study of the two MMMTs found in association with endometrial carcinoma and tubal carcinoma was inconclusiv e. CONCLUSIONS, Our study confirmed that primary peritoneal MMMTs were aggress ive tumors with poor prognosis. The presence of synchronous or metachronous genital carcinomas suggests multifocal tumorigenesis from tissue of same e mbryologic origin. The lack of hormone receptor in these tumors indicates d eviation from hormonal control. Specific BRCA-1 mutations found in ovarian carcinoma in Chinese patients could not be detected in our series. (C) 2001 American Cancer Society.