Diffuse malignant epithelial mesotheliomas of the peritoneum in women: a clinicopathologic study of 25 patients

The behavior of diffuse peritoneal mesotheliomas in women and the possible relation between tumor morphology and outcome are uncertain. Reported survival has ranged from < 1 month to > 14 years, and a previous study found that tumor morphology could not be used reliably for predicting outcome. The authors examined the behavior of diffuse epithelial peritoneal mesotheliomas in women and the possible relation between pathologic features and outcome.

Twenty-five female patients with diffuse peritoneal epithelial malignant mesotheliomas were divided into two groups: those who survived for < 4 years (60%) and those who survived for > 4 years (40%). Both groups were compared in terms of age, presentation, treatment, survival, tumor architecture, mitotic rate, necrosis, nuclear grade, and immunohistochemical profile.

Patients in the two groups were similar in terms of age at diagnosis (median ages, 50.7 years and 49.9 years), presentation, initial tumor burden, and treatment. In both groups, the most common initial clinical presenting features were ascites and abdominal pain. The tumors typically took the form of multiple nodules measuring < 1.5 cm in greatest dimension. Slightly less than 50% of patients in both groups received some form of chemotherapy or radiation therapy after undergoing tumor-reductive surgery or biopsy. Overall survival ranged from 1 month to 15 years. The median survival was 12 months in the group of women who survived for < 4 years and 7 years in the group of women who survived for > 4 years. Overall, 10 of 25 patients survived for > or = 5 years. One patient was alive with disease 15 years after diagnosis. Although there was a suggestion that the tumors in patients with short survival more often had solid architecture and high-grade nuclei, these findings were not significant statistically. The frequency of necrosis and the mitotic activity were the same in both groups.

The spectrum of diffuse epithelial peritoneal mesotheliomas in women includes tumors that are highly aggressive and behave much like pleural mesotheliomas, although a sizeable number of tumors, unlike the pleural tumors, are relatively indolent. However, because there do not appear to be morphologic features that reliably identify favorable tumors versus unfavorable tumors, aggressive therapy for all women with diffuse peritoneal mesotheliomas may be warranted.