Intrasubstance Schwannoma of Posterior Tibial Nerve Presenting as Lumbo-Sacral Radiculopathy

INTRODUCTION: Peripheral nerve tumours are rarely acknowledged as a cause of radiating pain in lower limbs and suspicion is almost always pointed towards lumbo-sacral causes. Schwannomas are tumours of peripheral nerve sheaths occurring anywhere along the peripheral nervous system. Often it can produce symptoms, which can be misleading in cases where obvious swelling is not present. The diagnosis may therefore be delayed by several years of emergence of symptoms. Very few such cases have been reported previously and none of them had an intrasubstance location of the tumour as in our case. CASE REPORT: We present a case of a middle aged female patient presenting with radiating pain in left lower limb, which was diagnosed and treated as lumbo-sacral radiculopathy for five years before an obvious swelling appeared, which on further investigations led to diagnosis of schwannoma of tibial nerve. Intraoperatively, the schwannoma was found to be intrasubstance in location which has never been reported in the past literatures making its excision, without damaging the conducting elements, a challenge. CONCLUSION: The possibility of peripheral nerve tumour should always be kept in mind while dealing with long standing cases diagnosed as radiculopathy and which do not get better with treatment on similar lines. A thorough clinical examination of the entire limb including Tinel’s sign can clinch the diagnosis earlier in cases where obvious swelling is not present. Even unusual presentations, as in our case, can be dealt surgically with good results.