A case of malignant pleural mesothelioma with gastrointestinal metastases which were diagnosed by endoscopic biopsy

: A 63-year-old man who had general malaise and dyspnea on effort, was admitted to our hospital. Chest X-ray film on admission showed left pleural effusion. Chest and abdominal CT after left chest drainage revealed left pleural thickening, mediastinal lymph node swelling, multiple lung nodules, osteolytic change of the left 4th rib, and multiple liver tumors. Right pleural effusion and ascites was also recognized. Cytology of the left pleural effusion suggested malignant mesothelioma. He had a skin tumor on his anterior chest. Biopsy revealed metastasis of malignant epithelioid mesothelioma. Upper gastrointestinal endoscopy showed a duodenal tumor and colonoscopy showed a cecal erosion. Endoscopic biopsy revealed metastases of malignant mesothelioma identical to the skin tumor. Because of the left pleural thickening, the primary site was considered to be in the left pleura. Here we report a case of malignant pleural mesothelioma (MPM) with multiple distant metastases to the duodenum, cecum, skin, lung, liver, and rib. Gastrointestinal metastases of MPM detected by endoscopic biopsy are very rare. Only one case of cecal metastasis has ever been reported.