Cytologic findings in multicystic peritoneal mesothelioma

The cytologic findings in a case of multicystic peritoneal mesothelioma are presented. A 70-year-old man had a slowly enlarging and intermittently painful abdominal mass that was multicystic and avascular on radiologic evaluation. Percutaneous drainage of the mass was performed over a four-year period for symptomatic relief. Large sheets of benign mesothelial cells were consistently present in the cytologic preparations of each of the drainage specimens. The mass has remained localized to the abdomen, and the patient is alive and well seven years after the onset of symptoms. The radiologic features and the clinical course of the patient were most suggestive of a rare benign multicystic peritoneal mesothelioma; the cytologic findings supported this diagnosis. A review of the pertinent literature is presented.