[A case of retroperitoneal ancient schwannoma in the pelvis]

We treated a case of retroperitoneal ancient schwannoma in the pelvis detected incidentally at a health examination without clinical manifestation in a 59-year-old Japanese man found to have hypertension. Computed tomography showed a heterogeneously enhanced 8 x 7 cm solid mass in the pelvic retroperitoneal space. Magnetic resonance imaging revealed an encapsulated tumor, showing a low intensity on the T1-weighted image, heterogeneously high intensity on the T2-weighted image and the tumor homogeneously enhanced with Gd-DTPA. It was suspected to be a mesenchymal tumor. The tumor was resected en bloc. The histologic examination of the extirpated tumor was an ancient schwannoma. A total of 11 retroperitoneal ancient schwannoma cases were reviewed.