Primary malignant mesothelioma developed in liver

The following reports a rare case of primary localized malignant mesothelioma of the liver. A 53-year-old man with no history of exposure to asbestos was admitted to our department for evaluation of incidentally detected liver mass. Computed tomography and hepatic angiogram showed a tumor at the dome of the liver, which was fed mainly through the inferior phrenic artery. The mass was resected, including a portion of the diaphragm. Microscopically, the tumor was composed of cord-like or trabecular arrangements of epithelioid cells having abundant eosinophilic cytoplasm and prominent nucleoli. Immunohistochemically, the tumor cells were strongly positive for calretinin and cytokeratin 5 and negative for hepatocyte markers. These findings were consistent with our diagnosis of epithelioid mesothelioma. A local recurrence was noted 15 months after surgery, which was treated by radiofrequency ablation. At 23 months after initial surgery, locally recurrent masses with direct invasion of the diaphragm and a solitary intrahepatic metastasis were noted, which was treated by partial excision of the diaphragm with intraoperative RFA after transarterial chemoembolization.