Malignant Peripheral Nerve Sheath Tumor Manifesting as Severe Buttock Pain

A 28-year-old woman presented with complaints of severe buttock pain exacerbating for 2 weeks. Physical examination found numerous café-au-lait macules and axillary freckles. Neurological examination revealed sensory loss at the S3-S5 dermatome and significant vesicorectal dysfunction. Magnetic resonance imaging revealed an enhanced intraspinal mass at S1-S2, with bony erosion on the dorsal aspect of the sacrum. Intraoperatively, the rostral part of the tumor was found to involve a filament of the cauda equina. The tumor protruded extraspinally through an irregular-shaped defect in the dorsal dura and bony erosion. Total resection was achieved. The histological appearance was consistent with malignant peripheral nerve sheath tumor and loss of neurofibromin. Malignant peripheral nerve sheath tumor should be included in the differential diagnosis of spinal tumor in a patient with neurofibromatosis type 1.