Medullomyoblastoma: report of two cases.

Two cases of medullomyoblastoma in children are described. The muscular component showed different features in the two cases and were associated with neuronal differentiation. Morphological, immunohistochemical, and electron microscopical findings are presented. The origin of the muscular component is discussed in relation to the findings in other cases of the literature. Both differentiation from primitive neuroepithelial cells and derivation from ectomesenchyme are considered.