Ectomesenchymoma: case report and review of the literature.

Ectomesenchymoma (EMCH) is a rare tumor that may arise in the brain or soft tissue. This tumor type is defined as a form including ectodermal components represented by neuroblasts or ganglion cells and differentiated mesenchymal structures of various types. The mesenchymal component is most often a rhabdomyosarcoma, but liposarcoma, malignant fibrous histiocytoma, leiomyosarcoma, chondrosarcoma, malignant schwannoma, and osseous elements have also been recorded. We report a case of an abdominal malignant ectomesenchymoma, containing three components, schwannoma, embryonal rhabdomyosarcoma, and ganglion cells, in a four-month-old infant. We also review 43 previously reported cases.