[Tumor enucleation for pelvic schwannoma: a case report]

A 36-year-old man with a complaint of pollakisuria visited our hospital. A non-displaceable, palm-sized tumor was palpable in the lower abdomen. Laboratory data were normal except for slightly high serum S100 protein. Intravenous pyelography revealed hydronephrosis on the right side and deviation of the bladder to the left. Computed tomogaphy revealed a heterogenous tumor in the pelvis with a cystic lesion and calcification. The tumor was 16 x 12 x 11 cm in size and in contact with the sacrum. The tumor was extirpated following diagnosis as a benign schwannoma by needle biopsy. The pelvic cavity was occupied by the tumor rigidly adhered to the sacrum. Although serious complications, such as bleeding and nerve injury were apprehended, we incised the tumor capsule and enucleated the contents as much as possible. The histopathological diagnosis of the resected specimen was benign schwannoma, type Antoni A. In the last 10 years, 37 cases of pelvic schwannoma have been reported in the Japanese literature. In most of them, surgical extirpation was difficult to perform because of adhesion to the sacrum. If the tumor is confirmed benign from histopathologic findings preoperatively, tumor enucleation may become a therapeutic option.