Cutaneous ganglion cell choristoma. Report of a case.

We describe the histological, immunohistochemical, and ultrastructural findings of a cutaneous tumour composed of ganglion cells, without any other proliferating component. As ganglion cells are not normal components of the skin, we propose the term "ganglion cell choristoma" for this lesion. The differential diagnosis of related lesions such as cutaneous ganglioneuroma, well-differentiated metastases from neuroblastoma, autonomic ganglia entrapped by neurofibroma, and reactive processes, and the possible histogenesis of ganglion cell choristoma are discussed.