From the Guidelines
Lumbar nerve sheath tumors are typically benign peripheral nerve sheath schwannomas and neurofibromas, which can be sporadic or associated with neurofibromatosis.
Characteristics of Lumbar Nerve Sheath Tumors
- Benign tumors: Most common are benign peripheral nerve sheath schwannomas and neurofibromas 1
- Malignant tumors: Malignant peripheral nerve sheath tumors are rare and occur more frequently in patients with neurofibromatosis 1
- Association with neurofibromatosis: Neurofibromatosis type 1 (NF1) is associated with an increased risk of developing malignant peripheral nerve sheath tumors (MPNST) 1
- Imaging characteristics: MRI can detect spinal causes of nerve root compression and signal abnormalities in the nerve root and plexus distal to the site of spinal neural compression 1
- Clinical presentation: Patients may present with pain, rapid growth, neurologic symptoms, and deep or truncal location of the tumor 1
- Treatment: Surgery remains the cornerstone of treatment for high-grade MPNST, with the aim of achieving clear margins 1
- Diagnostic tools: 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) and MRI can be used to diagnose and monitor lumbar nerve sheath tumors 1
From the Research
Characteristics of Lumbar Nerve Sheath Tumors
- The three main types of nerve sheath tumors are schwannomas, neurofibromas, and perineuriomas 2
- Spinal nerve sheath tumors are classified as intradural extramedullary spinal cord tumors, with an incidence of 3-4 per 1 million people 2
- Lumbar nerve sheath tumors can be asymptomatic, but any increase in size or presence of pain may indicate possible malignant degeneration 2
- Neurofibromas are composed of Schwann cells, fibroblasts, axons, perineurial cells, mast cells, and extracellular matrix 2
Clinical Presentation
- The most common initial symptom of malignant peripheral nerve sheath tumors (MPNST) is a painless mass 2
- Rapid increase in a subcutaneous mass or rapid onset of symptoms should raise suspicion of a malignant tumor 2
- Local or radicular pain is the most common pre-surgical symptom of spinal nerve sheath tumors, occurring in 80.8% of patients 3
Imaging Features
- Intravertebral mobile nerve sheath tumors are rare and can be identified by marked distortion and elongation of the carrier nerve on MRI 4
- Tumor texture, location, positional changes, and altered cerebrospinal fluid dynamics can contribute to tumor movement 4
- Multiple preoperative MRIs are important for localizing the tumor 4
Treatment and Outcome
- Surgical resection is the primary treatment for lumbar nerve sheath tumors, with total removal achieved in 94.5% of cases 3
- Subtotal resection may be necessary in some cases, and spinal fixation and fusion may be required for large or complex lesions 5, 6
- Clinical improvement can be expected in most patients, but complications such as recurrence, death, and radicular deficit can occur 5, 6