Working Diagnosis:
Severe spinal stenosis caused by two intradural extramedulluary masses.

Treatment:
The patient underwent neurosurgical resection including a laminectomy of T12-L1 and L3-L5 lesions. The specimen were sent for pathologic evaluation. During her hospitalization, she received inpatient physical and occupational therapy. Her course was complicated by a cerebrospinal fluid leak causing headache. She was discharged after 6 days with assistive devices including a 2-wheeled walker and right ankle foot orthosis.

Outcome:
The pathology report from her neurosurgical resection showed "circumscribed tumors composed of round monotonous tumor cells with clear cytoplasm in a background of extensive hyalinized collagen". Case Photo #5 There were no atypical features. These findings were consistent with a clear cell meningioma, which is defined as a CNS WHO grade 2 tumor. At her 1-month post-operative follow-up with neurosurgery, she subjectively reported 30% improvement in dorsiflexion strength; however, objectively, she demonstrated a 1+/5 strength with dorsiflexion. She was recommended to continue use of the right ankle foot orthosis, return to physical therapy in the outpatient setting, and gradually return to activity as tolerated. She was referred to neuro-oncology who recommended she undergo genetic testing due to the presence of 2 discrete tumors, which increases suspicion for a germline mutation causing these lesions. She was referred to radiation oncology who discussed a risk of recurrence for clear cell meningiomas as high as 30-40%. She was recommended to undergo radiation therapy but declined, opting instead for MRI surveillance every 6 months. She was able to return to running, however later reported to her primary care physician that she lacked any improvement in dorsiflexion strength 5 months after resection. She was ultimately referred back to physical therapy in the outpatient setting as well as the physical medicine and rehabilitation department to discuss other rehabilitative modalities.

Author's Comments:
Given her initial presentation and physical exam, it is often difficult to distinguish a peripheral common peroneal neuropathy from a central cause such as L5 radiculopathy. There are many overlapping motor functions with both diagnoses. Therefore, an electromyogram is often indicated for further diagnostic differentiation. Clear cell meningiomas may be sporadic or germline mutations in the SMARCE1 gene. Because the patient had 2 discrete tumors, it was thought that she likely possessed heterozygous mutations of SMARCE1. As a result, she had loss of tumor suppressor mechanisms leading to these lesions.

Editor's Comments:
The sports medicine consultants in this case appropriately identified a potential neurologic source of weakness and expeditiously obtained an electromyogram. While history and physical examination can be helpful to narrow the initial broad differential diagnosis of chronic ankle pain, final diagnosis requires astute clinical decision making and obtaining additional information via further testing. Ultimately, electomyographic testing allows the clinicians to direct this patient towards definitive treatment with neurosurgery.

References:
Kresak J, Yachnis A. Clear cell meningioma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cnstumorclearcellmeningioma.html. Accessed April 15th, 2024.
Rasooly R, Kniffin C. SWI/SNF-RELATED, MATRIX-ASSOCIATED, ACTIN-DEPENDENT REGULATOR OF CHROMATIN, SUBFAMILY E, MEMBER 1; SMARCE1. Online Mendelian Inheritance in Man website. https://omim.org/entry/603111. Accessed April 15th, 2024.

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