Obturator nerve schwannoma presenting as a laterovesical pelvic mass: A case report

Schwannomas arising from the obturator nerve are exceptionally rare benign peripheral nerve sheath tumors, often diagnosed only after resection because of their deep pelvic location and resemblance to gynecological, urological or nodal pathology. We report a 36-year-old man presenting with left groin pain radiating along the medial thigh, associated with progressive weakness of hip adduction. Pelvic ultrasound and magnetic resonance imaging both demonstrated a well-defined left latero-vesical mass along the course of the obturator nerve, with features suggestive of a benign nerve sheath tumor, including target and split-fat sign features and probable entering/exiting nerve fascicles, later corroborated at surgery. The patient underwent nerve-sparing surgical excision; the resected specimen weighed 9 g, and histology confirmed a benign spindle-cell tumor consistent with schwannoma. Symptoms resolved completely after surgery. This case highlights the characteristic presentation of obturator nerve schwannoma and its place in the differential diagnosis of a latero-vesical pelvic mass with obturator neuropathy.