[Large hairy pigmented spots in neurofibromatosis type 1: an atypical form of neurofibromas].

INTRODUCTION: Large hairy pigmented spots have been observed in patients with 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 pigmented spots with a diameter more than 3 cm were systematically notified. Realisation of the biopsy of the spot was proposed to the patient. RESULTS: Among 614 patients with neurofibromatosis type 1, seven (1.1 p. 100) had a large hairy pigmented spot. Biopsy was realized in six cases. In five 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 useful if it is necessary for the disorder diagnosis.