[The classification of atypical forms of neurofibromatosis].

Neurofibromatosis (NF) represents not an entity but a group of several forms which differ as to symptoms, prognosis and inheritance. In 1982 Riccardi suggested a classification into eight categories. Two of these--Von Recklinghausen NF-1 and bilateral acoustic NF-2- were defined in 1987 by a National Institutes of Health Consensus Development Conference. We describe 13 patients whose symptoms do not fit the diagnostic criteria for NF-1 and NF-2. 6 subjects can be classified as segmental NF-V. One of these patients was remarkable in having iris hamartomata, while his daughter was affected with NF-1. Another (female) patient in this group had areolar freckling, a finding not yet reported in NF patients. 4 cases belong to the late-onset NF-VII category, 3 of whom developed a neurofibrosarcoma. Two subjects are fist-degree relatives (mother and son). We are not aware of familial occurrence of NF-VII. Two further subjects were assigned to the variant form of NF, NF-IV. One patient had symptoms similar to NF-2 but the minimal diagnostic criteria were not fulfilled. Nevertheless, we consider his classification as NF-2 in view of a pattern of intracranial calcification repeatedly and exclusively found in NF-2. In general, assignment to a category of NF is important for appropriate patient management and genetic counselling. Classification of individual patients may be arbitrary at the time.