Malignant peripheral nerve sheath tumor with divergent differentiation.

Right posterior thigh malignant peripheral nerve sheath tumor with malignant glandular and rhabdomyoblastic components was diagnosed in a 24-year-old African American man. Malignant glands and rhabdomyoblastic cells were admixed with the spindle cells. Immunohistochemistry demonstrated spindle cells positive for S100 and vimentin; the glandular component was positive for chromogranin, and rare cells were positive for CK20 but negative for CK7. Rhabdomyoblastic cells were positive for muscle-specific actin and desmin. A single pulmonary metastasis occurred 5 months after surgical resection of the tumor. Death occurred 1 month later and was probably due to a pulmonary embolus.