Striated muscle-derived intraspinal choristoma: A case report.

Choristoma is a mass of tissue that is histologically normal for the organ or part of the body from which it originates, but is located at an abnormal site. Choristoma of the nervous system involves the occurrence of residual dysplastic tissues outside the nervous system and exhibits a low incidence. Thus far, there has been no prior report of intraspinal choristoma originating from the striated muscle. The patient in the present case was a young man who was admitted to the hospital wing to intermittent lumbago. A lumbar magnetic resonance imaging examination revealed a cystic-solid lesion in the spinal canal at the S1 level. Preoperatively, the lesion was suspected to be a teratoma and was therefore completely removed. The postoperative pathological report suggested that the mass was an intraspinal choristoma, a benign lesion associated with a good prognosis, which had originated from striated muscle. Early diagnosis and treatment can prevent progression of nerve dysfunction. The patient recovered well postoperatively and the symptoms of lower back pain disappeared. Although intraspinal choristomas are rare, when a lesion in the spinal canal is diagnosed, it should be considered in the differential diagnosis tumors.