Abstract: A healthy 52-year-old woman presented with 10-days history of back pain. Neurologic testing failed to detect any functional deficits in the upper and lower extremities, and the patient had a full range of cervical spine motion without associated pain. Spinal CT and MRI revealed a well-circumscribed intradural mass located at conus medullaris. The operation of L1 hemilaminectomy was performed, and pathological examination discovered dilatation of sweat ducts and suggested the diagnosis of ectopic sweat duct ectasia. IHC staining in epithelia immunophenotype showed: pan-cytokeratin (PCK)(+), epithelia membrane antigen (EMA)(+), P63(+), cytokeratin 5/6 (CK5/6)(+), gross cystic disease fluid protein 15 (GCDFP15)(-). Intraspinal ectopic sweat duct ectasia is extremely rare, which has not been reported in the literature to date.