Magnetic resonance-assisted neuronavigation for resection of deep pelvic nerve sheath tumors: illustrative cases.

BACKGROUND: Deep pelvic peripheral nerve sheath tumors (PNSTs) present unique surgical challenges due to their proximity to critical neurovascular structures. Conventional localization techniques may result in aborted procedures or subtotal resections. OBSERVATIONS: Two patients with suspected deep PNSTs underwent MR neurography (MRN) and CT-integrated neuronavigation-guided microsurgical resection. Patient 1, a 56-year-old woman with left-sided radicular pain, had a 1.5-cm lesion adjacent to the left sciatic nerve at S2. A prior resection was aborted due to difficulty localizing the tumor. MRN/CT-integrated neuronavigation enabled accurate identification and complete resection. At 1 year, she demonstrated improved ambulation, reduced pain, and no recurrence. Patient 2, a 72-year-old woman with recurrent radicular buttock pain, harbored a 4.9-cm mass at the sciatic notch. A prior nonnavigated resection was subtotal. Reoperation with neuronavigation enabled precise delineation of tumor margins, resulting in near-complete resection and symptom improvement. LESSONS: MR-assisted neuronavigation is a valuable adjunct for intraoperative localization of deep, anatomically complex suspected PNSTs, offering enhanced precision and improved safety. While safe resection depends on microsurgical technique and nerve monitoring, navigation-guided localization may reduce aborted procedures, facilitate confident surgical planning, and minimize iatrogenic injury. Broader validation through prospective studies is warranted to define optimal applications. https://thejns.org/doi/10.3171/CASE26540.