Medulloblastoma demonstrating multipotent differentiation: Case report

We report a 6-year-old boy who presented with a medulloblastoma demonstrating classic, myoblastic, neuronal, glial, and melanotic differentiation and manifesting as severe morning headache. Magnetic resonance imaging revealed a mass lesion with cystic components in the cerebellar vermis. He underwent suboccipital craniotomy and total resection of the tumor. The specimen consisted of three morphologically distinct components. The first component consisted of densely packed cells with round-to-oval highly hyperchromatic nuclei surrounded by scanty cytoplasm. Immunohistochemical staining revealed diffuse expression of neurofilament protein and focal expression of desmin and myoglobin. The second component consisted of long spindle-shaped cells with elongated nuclei and eosinophilic cytoplasm. Immunohistochemical staining revealed diffuse expression of neurofilament protein, desmin, and myoglobin. The third component consisted of cells with small, densely hyperchromatic nuclei and scanty cytoplasm in a fine fibrillary background. Mature ganglion cells and melanotic tumor cells were also observed. Immunohistochemical staining revealed diffuse expression of synaptophysin and neurofilament protein, and focal expression of glial fibrillary acidic protein, S-100 protein, desmin, and myoglobin. The diagnosis was medulloblastoma with myoblastic, neuronal, astrocytic, and melanotic differentiation. Medulloblastoma demonstrating multipotent differentiation is rare, but the features observed in this case support the idea that medulloblastoma originates from multipotent stem cells.