Delayed Presentation of Common Peroneal Nerve Schwannoma: Nerve-preserving Enucleation Under Loupe Magnification in a...

Schwannomas are benign peripheral nerve sheath tumors that can arise anywhere along the peripheral nerves. Schwannomas of the common peroneal nerve are rare and may present with nonspecific chronic leg pain, often resulting in delayed diagnosis, particularly in resource-limited settings. A 37-year-old man presented with a 2-year history of progressively worsening posterior knee pain radiating distally, described as sharp and electric-like. Physical examination revealed a tender mass in the popliteal region with a positive Tinel sign but no neurological deficits. MRI demonstrated an encapsulated lesion arising from the nerve at the sciatic bifurcation involving the common peroneal division. Fine-needle aspiration cytology was consistent with a benign spindle cell neoplasm. Microsurgical enucleation was performed under loupe magnification with preservation of nerve continuity. Histopathology confirmed schwannoma. Postoperatively, the patient had complete resolution of pain and preserved neurological function. Common peroneal nerve schwannomas, though rare, should be considered in patients with chronic neuropathic leg pain. Early imaging and meticulous microsurgical excision provide excellent functional outcomes.