Images of Memorable Cases: Case 91 91. Neurofibromatosis Type 1 The most common type of neurofibromatosis, affecting about one in 5,000 people. Diagnostic criteria for this autosomal dominant disorder include at least two of the following: 1) six or more café-au- lait spots larger than 5mm in diameter in children and larger than 15mm in teenagers and adults; 2) at least two neurofibromas of any type or one plexiform neurofibroma; 3) freckling in the inguinal or axillary regions; 4) optic nerve glioma; 5) two or more iris hamartomas (Lisch nodules); 6) a distinct osseous lesion; and 7) a first-degree relative (parent, sibling, or child) with type 1 neurofibromatosis. The 45-year-old patient shown had café-au- lait spots noted at birth and neurofibromas noted during puberty. Her mother had similar findings.