Medullomyoblastoma: teratoid nature of a quite rare neoplasm

Medullomyoblastoma is a quite-rarely reported biphasic histologic variant of medulloblastoma since the first published description of a tumor consisting of medulloblastic and myogenic elements. Controversy over its origin still goes on. Here, an additional case of medullomyoblastoma variant is reported, and discussed are the clinicopathologic features and pathophysiologic mechanisms of and treatment options for this neoplasm.

A 7-year-old girl was admitted to our clinic with headache, vomiting, and gait disturbances. An MRI scan on admission showed a solid tumor with a 2.5-cm axial diameter located in cerebellar vermis. The tumor was removed totally. Histologic examination revealed loose mesenchymal structures of the tumor and small muscle strands and isolated cells having large eosinophilic cytoplasm with striations. The muscular strands also demonstrated striations under light microscope. Glial fibrillary acidic protein, synaptophysin, and myogenin positivity are observed.

There are some strong evidences that the medullomyoblastoma may be a teratoma. Survival time with the tumor is very short, outcome is poor, and the tumor can spread along cerebrospinal fluid pathways. Total resection, chemotherapy, and craniospinal irradiation are mainstays of the treatment of medullomyoblastomas.