Schwannoma of the Sciatic Nerve as a Cause of Extra-articular Knee Pain: Case Report and Literature Review

INTRODUCTION: Schwannomas are rare benign tumors of the nerve sheath that originate from the Schwann cells of the peripheral nerve and have a broad anatomic distribution that includes superficial tissues, deep tissues, including the central nervous system, and the gastrointestinal system. CASE REPORT: A 60-year-old male presented with left knee pain for 5 years. This pain was associated with paresthesia, night pain unresponsive to analgesia, on the left foot intermittent pins and needles sensation. Schwannoma lesion was excised, histology confirmed the diagnosis, and the patient’s symptoms improved. CONCLUSION: Schwannoma around the knee is a rare or atypical cause of the non-arthritic pain and should be considered in the differential diagnosis of non-arthritic and extra-articular causes of knee pain with neurological deficit of the foot in an adult population.