Disclosures: Rachel Retallick, DO: Nothing to disclose

Case Description: The patient experienced insidious onset of sharp pain in the left leg localized to the medial calf with increase in severity and gradual progression to the medial thigh over the course of 2 years. Despite activity modification, the pain became more severe with incapacitating episodes of radicular pain down the left anterior thigh into the left calf with associated calf atrophy and lower leg fasciculations. Multiple specialists evaluated her over the course of 2 years and management included oral and topical NSAIDs, Neurontin and a spine injection (left L3 transforaminal epidural steroid injection) without relief.

Setting: Outpatient Physical Medicine & Rehabilitation Clinic

Patient: A 57-year-old active female runner with no significant past medical history.

Assessment/Results: Electromyography of the left lower extremity was unremarkable. MRI of the lumbar spine showed degenerative disc disease at L3-L4 and L4-L5 with mild bilateral foraminal stenosis at L4-L5. MRI of the left lower leg was unremarkable. Neuromuscular ultrasound of the left leg showed focal enlargement of the left femoral nerve distal to the inguinal ligament. The lesion was tender, hypoechoic, power Doppler negative, and measured 7.7mm in diameter. These findings were most consistent with a peripheral nerve tumor/neuroma. The patient underwent surgical excision of the neuroma without complications and Schwannoma was confirmed on surgical pathology of the biopsied specimen. At her 2-week postoperative follow-up she reported complete resolution of her pain.

Discussion: This is an uncommon etiology of neuropathic pain that should be considered in a patient with insidious onset of unilateral limb pain after workup is unrevealing of a common musculoskeletal or neurological disorder.

Conclusion: MRI has traditionally been used to identify a nerve lesion or tumor. However, neuromuscular ultrasound is also a useful modality for diagnosis of focal nerve pathology. If a nerve tumor/neuroma is identified on imaging, surgical biopsy is important to rule out a potential malignancy.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/unusual-etiology-of-chronic-neuropathic-leg-pain-in-an-active-middle-age-female-a-case-report/