Tibial Nerve Schwannoma: An Unexplained Cause of Lateral Foot Pain – A Rare Case Report and Review

Abstract

Introduction: Schwannoma is a benign tumor that arises from the peripheral nerve sheath. It presents as a discrete, often tender, and palpable nodule associated with neurogenic pain or paresthesia when compressed or traumatized. The growth rate is usually slow, and these lesions seldom exceed 2 cm in diameter. Case Report: We report the case of a schwannoma arising from the tibial nerve located in the left popliteal fossa. The patient presented with the left foot pain in the lateral plantar region without any motor deficit. The pre-operative diagnosis was made with magnetic resonance imaging (MRI) scan. He was subjected for neurolysis and excision biopsy of the lesion. The surgical specimen consisted of encapsulated white-yellow mass with irregular contours, measuring 2 × 3 cm. The cut section revealed cystic degenerations with areas of hemorrhage and necrosis. The patient reported symptom free in the post-operative period and during follow-up. Marginal excision appears to be recommended therapy for this tumorous lesion, without any evidence of recurrence during follow-up. Conclusion: A benign nerve sheath tumor of a peripheral nerve could be a possibility for long-standing neuropathic pain in the foot, ankle, and leg, wherein all other possibilities have been ruled out. The meticulous examination of the entire length of the tibial nerve including sciatic nerve by palpation and percussion was helpful in diagnosis which should be confirmed by MRI scan. The excision biopsy remains the gold standard treatment of choice for schwannoma of the peripheral nerve.

Ancient Schawanoma of radial nerve: a rare case report

“…In distal extremities involvement of lower limb is more common with 7 reported cases and tibial nerve is most frequently involved. 7 Ancient Schawannoma appear in patients between 20 and 70 years of age with males and females being equally involved. In the Upper limb they are classified into proximal and distal tumours.…”

The Rare Large Common Peroneal Nerve’s Schwannoma—A Case Report and Literature Review

“…The diagnosis of schwannoma is often late or misdiagnosed with other tumors, especially with Baker's cyst [3]. The large schwannoma is often presented in the spine [4,5], head, and neck (25%-45%) [6], while they represent approximately 5% of soft tissue neoplasm [1]. They rarely occur in the lower extremities, and in the popliteal fossa even more rarely [6,7].…”

“…The large schwannoma is often presented in the spine [4,5], head, and neck (25%-45%) [6], while they represent approximately 5% of soft tissue neoplasm [1]. They rarely occur in the lower extremities, and in the popliteal fossa even more rarely [6,7]. They often affect the posterior tibial nerve at around 8.9% [2,6], less in the sciatic nerve at around 1% [2,8], and even less frequently in the common peroneal nerve.…”

“…They rarely occur in the lower extremities, and in the popliteal fossa even more rarely [6,7]. They often affect the posterior tibial nerve at around 8.9% [2,6], less in the sciatic nerve at around 1% [2,8], and even less frequently in the common peroneal nerve. The common peroneal nerve due to its smaller size than the posterior tibial nerve and sciatic nerve is even less frequently affected by such tumors, with most schwannomas in this location measuring around 2 cm in diameter [9,10].…”

“…It feels hot, like burning in the right instep to the lateral ankle and lower leg. If the area is hit, the pain spreads from the lateral lower leg to the right instep (positive Tinel's sign), and the longer it feels thick (hypoesthesia) [2,6,7]. Surgery to remove the tumor is needed [6,7].…”