Malignant peripheral nerve sheath tumor arising in a "de novo" ganglioneuroma: a case report and review of the literature.

A case of a "de novo" ganglioneuroma showing a large area of malignant peripheral nerve sheath tumor (MPNST) is described. The tumor arose in an 11.5-year-old girl with neither stigmata nor family history of von Recklinghausen's neurofibromatosis. In addition, the patient had no previous history of a neuroblastoma or radiation therapy. This report provides new evidence that, although rare, the spontaneous development of an MPNST in a benign ganglioneuroma can occur. Immunohistochemical and electron microscopy studies supported the finding that the spindle cell component was of nerve sheath origin.