Pelvic malignant ectomesenchymoma: a case report

We report the case of a 19 month old boy referred to our institution becaus e of a pelvic tumor initially identified as an embryonal rhabdomyosarcoma a nd treated with surgery and chemotherapy. Eight years after the initial sur gery, a local tumor recurrence with bone metastasis was found, Histological examination and immunohistochemistry showed a double differentiation with both muscular and neuronal cells, This double differentiation was retrospec tively found in the initial tumor, then allowing the diagnosis of malignant ectomesenchymoma also called gangliorhabdomyosarcoma. This rare tumor, occ urring mainly during childhood, is composed of neuroblasts and/or ganglion cells and of malignant mesenchymal cells (usually rhabdomyosurcomatous cell s).