Karvonen S, Kallioinen M, Ylä Outinen H, Poyhonen M, Oikarinen A, Peltonen J. Occult neurofibroma and increased S100 protein in the skin of patients with neurofibromatosis type 1: new insight to the etiopathomechanism of neurofibromas. Arch Dermatol. 2000;136:1207-9 pubmed
..The skin of patients with NF1 might be more widely affected than previously thought and occult neurofibromas are not rare. ..