A case of primary diaphragmatic Schwannoma

A 59-year-old woman was admitted to our hospital for treatment of gallbladder stones. Ultrasonography showed multiple gallbladder stones and a hypoeochoic, homogeneous mass in the posterosuperior segment of the liver. A CT scan showed a well-defined, unenhanced round mass with a margin resembling the so-called "extra-pleural sign". This finding suggested that the tumor originated in the diaphragm adjacent to the liver. A preoperative diagnosis of primary diaphragmatic tumor and cholecystolithiasis was made, and resection of the diaphragmatic tumor and cholecystectomy were performed. Macroscopically, the resected tumor was 25 × 22 × 20mm in size, and it had a smooth connective tissue capsule. Based on the histological and immunohistological findings, the tumor was diagnosed as a schwannoma, "Antoni A type", originating in the diaphragm. Only 11 cases of primary diaphragmatic schwannoma have ever been reported, including 2 cases of malignant schwannoma, but the diagnosis of diaphragmatic schwannoma had never been made preoperatively. Surgical resection was performed in all 11 cases. Primary diaphragmatic tumors are rare, and malignant tumors account for approximately 40% of the total. Primary diaphragmatic schwannoma is very difficult to diagnose preoperatively. Whenever a primary diaphragmatic tumor is diagnosed, it should be resected.