A Rare Case of Melanotic Schwannoma Occurred Intraosseous of Sacrum: A Literature Review

Abstract

Background: Melanotic schwannoma is a rare tumor when it occurs in the sacrum. Though it is mostly classified as benign, the prognosis is unpredictable due to the possibility of recurrence and metastasis. Here, we reported a case of intraosseous of sacrum with good results and reviewed the literature.Case Presentation: A 33-year-old male patient complained of low back pain and was discovered to have an obstruction at S2. Following the necessary imaging diagnosis, we treated the patient with piecemeal excision in conjunction with extended curettage, and the frozen biopsy revealed that the tumor was melanotic schwannoma. The intraosseous portion of the lesion was curettaged using high-speed drill to enlarge the edge of curettage, and piecemeal excision for lesion within the sacral canal. After surgery, the patient received total 56Gy radiotherapy and frequent follow-up. After 15 months follow-up, there was no evidence of recurrence, and the nerve function was normal. Conclusion:Melanotic schwannoma that occurs intraosseous of the sacrum is extremely rare and lacks typical clinical manifestations; however it can be identified through careful pathological and imaging diagnosis. Intralesional extended curettage combined with radiotherapy can achieve a good local control with a satisfactory clinical effect in this rare disease.

Malignant melanotic schwannoma of the cervical spinal cord: a case report

“…It belongs to a highly malignant tumor, the recurrence rate of MMNST may be as high as 35% and the rate of distant metastasis as high as 44%, and has a poor prognosis. The cause of MMNST is unknown, and may be related to genetic factors, radiation exposure or malignant transformation of neurofibromas [6,7]. Treatment of malignant melanotic schwannoma is mainly surgical, and in principle, radical resection is required.…”