A large abdominal wall mass as an initial manifestation of malignant mesothelioma.

Malignant mesothelioma is relatively rare and usually presents with pleural thickening and effusion at onset. In this report, we describe a 67-year-old male patient whose initial manifestation of mesothelioma was a large mass in the left flank. Mesothelioma was diagnosed from needle biopsy specimens, and, after radiotherapy, the tumor did not recur in this area. However, pleural effusion developed, which was controlled by pleurodesis, and tumors appeared around the descending aorta. Despite further radiotherapy, the patient died of cardiac tamponade due to tumor invasion 38 months after the initial diagnosis. To the best of our knowledge, this is the first description of malignant mesothelioma presenting via initial invasion of the abdominal wall without changes in the thoracic space.