[A case of colonic polypoid ganglioneuromatosis--a light microscopy, electron microscopy and immunohistochemical study].

A 68-year-old man with colonic polypoid ganglioneuromatosis is reported. He had manifested no signs and symptoms of von Recklinghausen's disease and/or a multiple endocrine neoplasia syndrome. A single polyp was found by a barium enema and an endoscopic polypectomy was performed. Light microscopy showed the propria mucosa of the polyp was composed of a proliferation of spindle cells with a fibrillar cytoplasma and large cells with a round large nucleus, a prominent nucleolus, and vast cytoplasm. Some crypts were slightly dilated. Random biopsied specimens from the colonic normal mucosa showed focal proliferation of only the spindle cells. Electron microscopically, the spindle cells consisted of Schwann cells forming neurites, and large cells that coincided with the features of ganglion cells. Immunohistochemically, the localization of neuron specific enolase was demonstrated in the cytoplasm of these cells. These findings led to a diagnosis of colonic polypoid ganglioneuromatosis, and the pertinent literature is reviewed.