Pathophysiology of neurofibromatosis. IV. Dermatologic insights into heterogeneity and pathogenesis.

A systematic, uniform evaluation of 102 patients with, or at risk for, neurofibromatosis has shown that café au lait spots (CLS), even in large numbers, may not be sufficient to diagnose this disorder, and that several other dermatologic features may provide clues to its pathogenesis. These features include pruritus associated with high concentrations of cutaneous neurofibromas, hyperpigmentation overlying plexiform neurofibromas, two levels of hyperpigmentation in some CLS, hypopigmentation in surgical scars through CLS, and areolar neurofibromas in postpubertal females. Iris Lisch nodules (hamartomas) are present in 97% of postpubertal patients.