Peripheral neuroepithelioma with ganglion cells: report of two cases and review of the literature.

Peripheral neuroepitheliomas, also known as peripheral primitive neuroectodermal tumors, are by definition primitive embryonal lesions generally composed of poorly differentiated neuroectodermal elements. We have examined two cases that paradoxically contain extensive foci of ganglionic differentiation similar to that of ganglioneuroblastoma, in addition to primitive elements. One tumor arose from the chest wall of an 8-year-old male and the other from the abdominal wall of a 15-year-old male. Differentiation into a mature ganglionic phenotype was confirmed by immunohistochemistry in one case. Rare peripheral neuroepitheliomas have a capacity for maturation that is not generally appreciated. These lesions should not be confused with ganglioneuroblastomas, which are genotypically unrelated neoplasms.