Adult neuroblastoma. Electron microscopic observations in nine cases.

Nine patients, whose ages ranged from 18 to 72, had small round cell neoplasms which were found on electron microscopy to have the ultrastructural features of neuroblastoma. The primary tumor was retroperitoneal in one patient. In another, liver and bone metastases were present and the primary site was not determined. The tumor presented in a peripheral location in the remaining seven patients (leg in two, buttock in one, head and neck in four), and all seven tumors metastasized to regional lymph nodes. One tumor that arose in the nasal cavity displayed olfactory differentiation. Two tumors recurred locally following excision. Although two patients have died from disseminated disease, the prognosis nevertheless appears more favorable than in childhood neuroblastoma. Adequate local excision of a peripheral lesion with close follow-up are indicated.