What is the diagnosis for a 74-year-old female presenting with pain and weakness in the left lower extremity, with Magnetic Resonance Imaging (MRI) findings of a benign nerve root sheath tumor at the L2-L3 level and multilevel lumbar disc degeneration with associated foraminal stenosis and facet arthropathy?

From the Guidelines

The patient's symptoms of left lower extremity pain and weakness are most likely caused by the combination of the benign nerve root sheath tumor at the L2-L3 level and the degenerative changes with foraminal stenosis, particularly on the left side at L4-L5 and L5-S1, and management should prioritize a multidisciplinary approach including neurosurgical consultation, physical therapy, and pain management. The MRI findings reveal multiple spinal issues, including a benign nerve root sheath tumor (likely a schwannoma or neurofibroma) at the L2-L3 level affecting the left L2 nerve root, which has been present long enough to cause remodeling of adjacent bone 1. Additionally, there are multiple levels of degenerative disc disease with disc protrusions, particularly severe at L5-S1, and moderate to severe foraminal stenosis at multiple levels, especially on the left side at L4-L5 and L5-S1.

According to the most recent guidelines, MRI is the preferred imaging modality for evaluating patients with persistent back and leg pain who are potential candidates for invasive interventions 1. The goal of imaging is to identify potential actionable pain generators that could be targeted for intervention or surgery. In this case, the MRI findings suggest that the nerve root tumor and left-sided foraminal stenosis are the most likely causes of the patient's left leg symptoms.

Management should include:

• Neurosurgical consultation for evaluation of the nerve sheath tumor, which may require surgical removal if it's causing significant compression
• Conservative management with physical therapy, pain medication (NSAIDs, muscle relaxants, or gabapentin for neuropathic pain), and possibly epidural steroid injections to manage symptoms from the degenerative changes
• A multidisciplinary approach involving neurosurgery, pain management, and physical therapy to address both the tumor and the degenerative changes contributing to her symptoms.

It is essential to consider the patient's age and multiple pathologies when developing a treatment plan, and to prioritize a approach that minimizes risks and maximizes benefits in terms of morbidity, mortality, and quality of life 1.

From the Research

MRI Findings and Diagnosis

• The patient's MRI findings indicate a prominent benign nerve root sheath tumor within the left foramen at the L2-L3 level, with remodeling of adjacent osseous structures and probable involvement of the left L2 nerve root 2.
• The findings also show advanced disc degeneration at the L5-S1 level, with broad-based posterior disc protrusion and endplate ridging, contributing to moderate left and mild right foraminal stenosis 2.
• Additionally, there is disc degeneration at the L1-L2 and L3-L4 levels, with broad-based posterior disc protrusions and facet arthropathy, contributing to moderate right and mild left foraminal stenosis 2.

Treatment and Management

• The treatment of spinal nerve sheath tumors, such as the one found in this patient, typically involves surgical resection, which can be associated with complications, including new or worsening neurological deficits 2, 3.
• The use of intraoperative neuromonitoring has been shown to be associated with a higher rate of gross-total resection and may help reduce the risk of complications 2.
• Epidural steroid injections may be a viable alternative pain treatment for patients with spinal malignancy-related pain, with some studies showing significant pain relief and no adverse events 4.

Differentiation of Malignant and Benign Tumors

• Conventional MRI and diffusion-weighted imaging (DWI) can help differentiate malignant from benign peripheral nerve sheath tumors, with features such as tumor size, margin, and presence of perilesional edema being significant predictors of malignancy 5, 6.
• The absence of a split fat sign and mean apparent diffusion coefficient (ADC) values have been identified as robust imaging findings distinguishing malignant from benign peripheral nerve sheath tumors 5.