Large hairy pigmented spots in neurofibromatosis type I: an atypical aspect of neurofibromas.

Introduction. Large hairy pigmented spots have been observed in patients wi th neurofibromatosis type 1. In this study we tried to determine the nature and the frequency of these hairy pigmented spots in neurofibromatosis type 1. Patients and methods. In patients with neurofibromatosis type 1, hairy pigm ented spots with a diameter more than 3 cm were systematically notified. Re alisation of the biopsy of the spot was proposed to the patient. Results. Among 614 patients with neurofibromatosis type 1, seven (1.1 p. to o) had a large hairy pigmented spot. Biopsy was realized in six cases. In f ive cases, diagnosis was superficial and plexiform neurofibroma, the 6(th) case was a Becker's nevus. Conclusion. Large hairy pigmented spot is a rare aspect of superficial and plexiform neurofibroma during neurofibromatosis type 1. A biopsy may be use ful if it is necessary for the disorder diagnosis.