Retroperitoneal malignant peripheral nerve sheath tumor

Primary retroperitoneal neoplasms are a rare entity and account for 0.1%–0.2% of all malignancies. In addition, only 1% of malignant peripheral nerve sheath tumors (MPNSTs) occur in retroperitoneal region. Herein, we report a case of retroperitoneal peripheral nerve sheath tumor in a 50-year-old man who presented with right lower limb pain. On physical examination, an abdominal mass was palpable. Computed tomography of abdomen with contrast, showed a large, lobulated mass, in the right paravertebral region extending to the middle area of abdomen and pelvis. The patient underwent exploratory laparotomy and mass excision. Histopathological examination was consistent with “MPNSTs.” This case report emphasizes that, although rare, MPNSTs may arise from retroperitoneal region. They have varied clinical presentations, and combination of microscopic, radiological, and immunohistochemical analysis is needed for diagnosis of MPNSTs.