Cerebellar medullomyoblastoma with melanotic tubular structures

This report describes a midline cerebellar primitive neuroectodermal tumor with muscular differentiation, that is, medullomyoblastoma with melanotic tubular structures, which developed in the cerebellar vermis in a 23-month-old male. Rhabdomyoblastic differentiation consisted both of striated muscle fibers and undifferentiated cells showing immunoreactivity for desmin and myogenic transcription factors. The presence of melanotic epithelial structures raised the issue of a teratomatous tumor. This case demonstrates the occurrence of this very rare tumor in early childhood as well as the utility of a careful search for the presence of myogenic and/or melanotic features in medulloblastomas.