100 - Combat Boot-Associated Tibial Neuroma in a Military Service Member

Schwannomas are benign peripheral nerve sheath tumors that can cause significant discomfort and functional impairment. The etiology of schwannomas is unknown, but prior trauma has been reported as a potential contributing factor. This report presents a case highlighting the use of neuromuscular ultrasound (US) to expedite the diagnosis of a tibial nerve schwannoma in an active duty Service Member (ADSM) with primary aggravating factor of donning combat boots.

Case Description:

A 42-year-old male presented with a two-year history of chronic left ankle and foot pain following prior surgery for fibular tendon pathology. Medial ankle and foot pain persisted post-operatively with newer onset of paresthesias within the tibial nerve distribution. Clinical examination (e.g., positive Tinel’s sign at combat boot level height) raised concern for tibial neuropathy prompting referral for diagnostic US examination, which revealed a lesion consistent with a tibial neuroma. The patient was referred for additional imaging (i.e., MRI) and neurosurgery consult. MRI findings were suggestive of a peripheral nerve sheath tumor leading to successful surgical resection of a pathology-confirmed schwannoma. At 3 months, the patient reported marked pain and symptom reduction and return to duty-level physical activity.

Discussions:

Schwannomas are rarely symptomatic within the lower extremity, which presents a diagnostic challenge due to overlapping symptoms with other pathologies. Neuromuscular US played a critical role in localizing the lesion in this ADSM, which led to an expedited diagnosis and multi-disciplinary treatment plan. In this case, surgical intervention led to rapid symptom relief and functional restoration.

Conclusions:

This case illustrates the diagnostic utility of neuromuscular US in evaluating tibial nerve pathology in an ADSM with chronic foot and ankle pain. US provided a non-invasive, real-time modality to guide clinician decision-making. Prompt diagnosis and targeted treatment are essential for preserving operational readiness in military populations with peripheral nerve pathology.