A 56-year-old woman was admitted to our hospital with the chief complaint of left back pain. We detected left pleural effusion on chest X-ray and performed chest drainage. No malignant cells were detected in the effusion. Chest CT demonstrated a tumor shadow over the left diaphragm and left pleural effusion 6 months later. She underwent en bloc resection of the tumor and left diaphragm. Histological evaluation revealed malignant fibrous histiocytoma (MFH). Recurrent tumors were found in the abdomen 8 months after the operation, and she underwent resection of the abdominal recurrent tumors. Histological evaluation of the recurrent tumors also showed MFH. The patient died 28 months after the first operation.