Plexiform schwannomas of the sciatic nerve:a case report and review of the literature.

Background: Schwannomas grow slowly, mainly in the head and spine. The extremities schwannomas are rare and easily missed, particularly in patients who also have lumbar disc herniation in addition to sciatic schwannomas. We present a unique case of sciatic schwannoma , which has been considered as a lumbar disease in the past until an MRI of the thigh. Case presentation: A 43-year-old female complained of pain in her low back and left thigh for 10 years. Physical examination showed that her left thigh was swollen and positive Tinel sign. On MRI, we found a series of tumors suspected of schwannomas at the back of her left thigh. After obtaining the patient's consent, we performed intracapsular excision of her tumors. Histological examination of the tumors were consistent with plexiform schwannomas. The patient recovered well after operation and there was no sign of nerve injury or recurrence after follow-up for 11 months. We searched the Pubmed database and found 31 published reports about sciatic schwannomas. Conclusions: Sciatic schwannomas usually occur in middle-aged women, and the main symptom is pain. In addition to palpation, we should pay attention to Tinel sign during physical examination. MRI is very helpful for diagnosis, but histological examination is the only way to make a final diagnosis. Intracapsular resection is the best method for the treatment of schwannomas, although there is still the possibility of recurrence after operation.