Riccardi and Eichner (1986) designated the classic von Recklinghausen disease (162200) as neurofibromatosis I (NF1) and familial acoustic neuromas (101000) as neurofibromatosis II (NF2). They suggested the existence of an entity they labeled NF III that combines features ... Riccardi and Eichner (1986) designated the classic von Recklinghausen disease (162200) as neurofibromatosis I (NF1) and familial acoustic neuromas (101000) as neurofibromatosis II (NF2). They suggested the existence of an entity they labeled NF III that combines features of both with some additional distinctive features. Cafe-au-lait spots (CLS), freckling, and cutaneous neurofibromas occur as in NF I, although typically the CLS are few in number and pale and may be relatively large, and cutaneous neurofibromas are few in number. The palm of the hands is a characteristic site for cutaneous neurofibromas in NF III. Iris Lisch nodules do not occur. Bilateral acoustic neuromas, posterior fossa and upper cervical meningiomas, and spinal/paraspinal neurofibromas are the predominant features of NF III, but optic gliomas have not been seen. The CNS tumors make their presence known usually by the second or early third decade and develop rapidly thereafter. The natural history and therefore the prognosis are different from that of classic von Recklinghausen disease. A relatively rapid and fatal course from multiple CNS tumors is usual.