[An autopsy case of desmoplastic malignant mesothelioma]

On November 15, 2000, a 60-year-old man was admitted to our hospital with progressive dyspnea and right chest pain. He had a 40-year history of occupational asbestos exposure, which began when he was 20 years old. On admission, his chest radiographs showed pleural effusion on the right side, and asbestos bodies were detected in his sputum. Neither a cytological examination of the pleural effusion nor a histological examination of the pleura by percutaneous pleural biopsy revealed malignant cells. In addition, we could not find any other cause for the pleural effusion (such as tuberculosis, collagen disease, or heart failure). In May 2001, the patient also developed pleural thickening and pain in the right hypochondrium, and he was readmitted to our hospital on May 21, 2001. On readmission, an enhanced abdominal CT showed multiple liver tumors, and percutaneous pleural and liver biopsies were performed. The histological findings in the pleura and liver specimens revealed hypocellular collagen tissues without malignant cells. Thus, we could not determine the main cause either of the pleural effusion or of the patient's disease. However, his condition rapidly deteriorated, and he died on August 12, 2001. At the autopsy, bilateral pleural thickening, predominantly on the right side, and invasion of the lungs were observed. The histological findings in the pleural and hepatic tissues revealed hypocellular collagen fibers with a striate pattern and areas of neoplastic spindle cells. He was diagnosed as having malignant desmoplastic mesothelioma with liver metastasis. Cases of malignant desmoplastic mesothelioma have rarely been reported in Japan.