A 10-year-old boy has multiple tan-colored patches on his skin, and freckle-like skin changes in his armpit area. The rest of clinical examination is normal. Which of the following conditions is also found in patients with this disorder as they get older?

The two common forms of neurofibromatosis (NF-1 and NF-2) are genetically distinct. NF-1 is the type with multiple cafe au lait spots and is associated with axillary or inguinal freckling, iris hamartomas (Lisch nodules), peripheral neurofibromas, and bony abnormalities (including kyphoscoliosis). NF-2 is associated with CNS tumors, particularly bilateral eighth nerve tumors. Skin lesions are spare or absent, and early lens opacities can occur.