Summary: A pelvic schwannoma is an extremely rare, benign tumor that arises from the myelin sheath of peripheral nerves. When it grows deep in the retroperitoneal space of the lesser pelvis, it can mimic degenerative spinal disease by compressing sacral nerve roots, producing severe, persistent sciatic pain and risking lower limb paralysis. Because the pelvis contains a dense network of motor and autonomic nerves controlling leg movement, bladder, bowel, and reproductive functions, surgical removal in this confined area carries significant neuro-urological risks.
In a high-profile, five-hour operation, an interdisciplinary surgical team performed a minimally invasive laparoscopic excision of a five-centimeter pelvic schwannoma in a young woman. Using advanced intraoperative electrophysiological neuromonitoring, surgeons identified and protected functional nerve bundles, resolving the patient’s pain and restoring full mobility.
Key Facts
- Diagnostic challenge: Pelvic schwannomas represent only 1–3% of all nerve-sheath tumors and often present with sciatica-like symptoms. Because the pain radiates to the sacrum and leg, these tumors are frequently misdiagnosed as degenerative spinal disk disease.
- Intraoperative neurophysiology: The team used a 32-channel mobile electrode neuromonitoring system to map nerve function in real time, distinguishing functional nerve fibers from tumor tissue during dissection.
- Function preservation: Monitoring allowed the surgeons to protect motor nerves supplying the right leg and the autonomic nerve bundles that control the rectum, bladder, vagina, and uterine fertility.
- Fragmented “open door” excision: After using neurostimulation to gently elevate and separate nerve roots from the tumor surface, the mass was removed in controlled fragments to minimize bleeding in a vascular pelvic space.
- Regional center of excellence: Semmelweis University’s Neuropelveology Program is the only specialized center in Central and Eastern Europe performing continuous intraoperative neuromonitoring for these cases, alongside a small number of teams in France and Switzerland.
- Rapid recovery: The muscle-sparing laparoscopic approach enabled the patient to be discharged fully ambulatory and pain-free the day after surgery.
Source: Semmelweis University
Interdepartmental teamwork restored a young woman’s walking ability and quality of life after laparoscopic removal of a rare pelvic schwannoma.
Semmelweis University’s Neuropelveology Program, within the Department of Obstetrics and Gynecology, collaborated closely with the Department of Neurosurgery and Neurointervention to perform the operation with continuous intraoperative electrophysiological monitoring. The joint team includes Dr. Loránd Erőss, Director of the Department of Neurosurgery and Neurointervention, electrophysiologist Dr. Boglárka Hajnal, and neurology resident Dr. Borbála Damó-Csorba, working alongside the Department of Obstetrics and Gynecology team led by Associate Professor Dr. Attila Bokor.
The operation took place on May 6, 2026, and attracted international attention. The patient presented with unrelenting pain radiating into her right leg caused by a five-centimeter tumor located behind the uterus at the site where a sacral nerve exits the pelvis. Because the pain pattern closely resembles common spinal conditions such as disc degeneration and sciatica, pelvic schwannomas are frequently overlooked during initial evaluations focused on the spine.
What is a neurinoma or schwannoma?
A neurinoma (also called a schwannoma) is a slow-growing benign tumor of the Schwann cells that form the myelin sheath around peripheral nerves. These tumors are rare, with an incidence of about 0.3–0.5 cases per 100,000 people, and can appear anywhere peripheral nerves exist. The most common type is the vestibular schwannoma, which affects the eighth cranial nerve and accounts for a notable share of intracranial tumors.
Because the tumor lay in a confined and highly vascular pelvic region and had begun to affect more than one nerve root, the surgical team planned the operation with extreme caution. Preserving urinary, bowel, and sexual function, as well as future fertility, was prioritized in addition to relieving pain and removing the mass.
During the roughly five-hour procedure, neurosurgeons used a 32-channel electrode connected to a mobile neuromonitor to assess the tissue before and during resection. Micro-electric pulses delivered through the monitoring system identified functional nerve bundles by generating immediate feedback if stimulation produced a response. This mapping enabled the surgeons to selectively peel functional nerves off the tumor surface and to resect the tumor in several pieces while avoiding injury to vital structures.
Dr. Loránd Erőss highlighted that the main neurosurgical challenge was precisely localizing the tumor laparoscopically in this deep pelvic location. He credited Dr. Attila Bokor’s laparoscopic expertise with overcoming that difficulty. Dr. Bokor emphasized that the strategy of fragmenting the mass and continually testing nerve function provided important safety margins in an area prone to bleeding and complex anatomy.
To support ongoing collaboration and future cases, the team acquired a dedicated mobile neuromonitoring device. This equipment is also useful for delicate pelvic procedures such as excising endometriotic lesions that involve nerves, and for treating vascular compressions and fibrosis-related complications following prior surgeries or radiation therapy.
Semmelweis surgeons estimate they perform a small number of planned neuropelveological procedures each quarter, a caseload unique in Hungary and neighboring countries and comparable to only a few European groups. The early May operation was observed live by specialists from several countries and concluded successfully: the patient was pain-free, at no risk of lower limb paralysis, and discharged the next day. Follow-up care includes MRI scans at three months and one year to monitor for recurrence.
Key Questions Answered:
A: Retroperitoneal pelvic schwannomas are extremely rare (under 3% of schwannomas). They slowly enlarge and compress sacral nerve roots, producing classic sciatica-like pain that leads clinicians to focus on spinal causes. As a result, imaging and examinations directed at the back can miss a hidden pelvic mass.
A: The pelvis is a compact, high-risk area where motor nerves for walking and autonomic nerves for bladder, bowel, and sexual function are closely interwoven. During surgery, a 32-channel mobile electrode delivers small electrical stimuli to the tissue before cutting. If the monitor detects a response, the team knows a functional nerve is present and alters the dissection accordingly. This real-time mapping allows surgeons to separate and preserve nerve fibers before tumor removal.
A: Treating complex pelvic nerve conditions requires specialized skills that combine advanced gynecologic laparoscopy, neurosurgical techniques, and intraoperative electrophysiology. Semmelweis operates the only dedicated program in Central and Eastern Europe offering continuous intraoperative neuromonitoring for these cases, enabling treatment of rare nerve compressions, vascular entrapments, and deep endometriosis affecting pelvic nerves.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper associated with the case was reviewed in full.
- Additional clinical context was provided by staff contributors.
About this neurosurgery and cancer research news
Author: Robert Cseszregi
Source: Semmelweis University
Contact: Robert Cseszregi – Semmelweis University
Image: The image is credited to Neuroscience News