POPLITEAL CYSTIC SCHWANNOMA MIMICKING BAKER CYST – AN UNUSUAL CASE PRESENTATION – CASE REPORT

Abstract

Introduction: Schwannoma is the most common tumor of peripheral nerves. They are usually solitary, encapsulated, homogenous slow growing masses, sometimes associated with pain and paresthesia.We present a case of schwannoma in an unusual location. Case presentation: A 16 year old boy presented to surgical OPD with a slow growing left popliteal swelling for 6 months and neuralgia for 1 month. The swelling decreasing on knee exion. Based on clinical suspicion patient was operated for popliteal cyst. Intraoperatively there was close association with nerve and it was difcult to dissect from nerve. So it was thought of being a nerve tumor. Surgical excision was done. Histopathological examination revealed it to be Cystic Schwannoma. Discussion: Schwannoma is the most common benign neoplasm of peripheral nerves. Cystic degeneration and repeated hemorrhages (10%) can occur sometimes. There are two types of tissues in Schwannoma – Antoni A and Antoni B.Schwannoma varies from 2-20 cm in diameter. It is not localized to any specic area; it can occur anywhere along peripheral nervous system in neck, mediastinum, retroperitoneum, pelvis, upper extremities. It is extremely unusual in lower limb of which tibial nerve is uncommon site. Conclusion: Diagnosis of schwannoma originating from lower extremity peripheral nerves may be delayed because it can be misdiagnosed as Baker's Cyst or the symptoms of the patient can be thought as a result of lumbar disc herniation.Thorough clinical examination and investigations, conrms the diagnosis, as management is different for both.