Retroperitoneal Ancient Schwannoma: A Benign Tumor

Schwannomas are uncommon benign neoplasms arising from the Schwann cells lining the nerve sheath. Retroperitoneal schwannomas are extremely rare constituting about 0.3‐3.2% of all retroperitoneal masses. Pancreatic schwannomas are obsolete and less than 50 cases reported until date in the literature. Ancient schwannomas is a histological variety in which there would be degenerative changes occurring with increasing duration of these tumors. We report 4 cases of retroperitoneal ancient schwannomas with one of pancreatic origin. Patients underwent pre‐operative imaging studies (computed tomography/ magnetic resonance imaging). All cases underwent exploration and en bloc excision of the tumors. The diagnosis was confirmed on both histopathological and immunohistochemical analysis. Pre‐operative diagnostic dilemma in retroperitoneal schwannomas arises as they are either asymptomatic or have vague symptoms and signs. The radiological findings are not characteristic in the majority of the time. Fine‐needle aspiration cytology is inconclusive and accessibility is always challenging due to its location. Pancreatic ancient schwannoma described here is unique due to the extreme rarity of location and was diagnosed intraoperatively on frozen section. As most of these tumors are in the paravertebral position in close proximity to important neurovascular structures it causes a technical challenge for a surgeon to operate. Resection of the tumor in toto is the treatment of choice for all tumors.