Myxoma of the nerve sheath. Report of three cases, observations by light and electron microscopy and histochemical analysis.

Findings by light and electron microscopy and histochemistry in three cases of myxoma of a nerve sheath are presented. The histochemical findings are compared with those obtained in identical studies done on two benign schwannomas, two neurofibromas, and a soft tissue myxoma. In addition, myxomatous changes in a peripheral nerve obtained at vagotomy were similarly studied. Morphologically, myxoma of the nerve sheath is a distinct neoplastic entity showing moderate cellular atypia and a characteristic tissue distribution. Histochemically, the neoplasm shows a mucopolysaccharide profile that categorizes it as a neoplasm of mesenchymal origin rich in highly sulfated acid mucins. Of particular note is its close histochemical similarity to a neurofibroma.