Giant retroperitoneal lumbar Schwannoma: A case report and review of literature

Schwannomas are benign peripheral nerve sheath tumors arising from Schwann cells. Retroperitoneal localization for schwannomas is extremely rare (%3). The primary surgical approach for such tumors is total resection. This study aimed to report the case of a schwannoma with giant, retroperitoneal extension originating from the L3 nerve root.
A 43-year-old female patient was admitted to the department with a cellulosic schwannoma pathology after excisional biopsy at another center. The patient's neurological examination was normal. The lumbar–abdominal contrast-enhanced magnetic resonance imaging (MRI) of the patient revealed a mass lesion in the vertebral compartment 2 × 3 × 3 cm³ and psoas component 8 × 4 × 3 cm³ in size, extending from the right L3 nerve root into the right psoas muscle. The patient was operated postoperatively in the first stage and then using the anterior approach with intraoperative neuromonitoring. Postoperative contrast-enhanced MRI showed no enhancing tumoral lesions. The pathology result was compatible with schwannoma World Health Organization Grade 1.
Two-stage surgical procedure in such cases should be preferred to prove the adequacy of the surgical field and avoid the complications that may occur in neighboring anatomical structures during resection of circumferentially circumscribed tumors.
Urgent surgical intervention is needed for retroperitoneal lumbar schwannomas. Moreover, elective surgery planning is necessary, and preoperative evaluations should be performed.