Association of urticaria pigmentosa with café-au-lait spots, neurofibromas and neurofibroma-like neoplasms: a mere coincidence?

BACKGROUND Urticaria pigmentosa (UP) is characterized by dense aggregates of mast cells in the dermis. There is consistent evidence from the literature that mast cells may play a pathogenetic role in the development of neurofibromas and other tumors. OBJECTIVE To study the concomitant appearance of UP with neurofibromas and neurofibroma-like neoplasms. METHODS We analyzed 31,752 records of patients examined at the Department of Dermatology in the year 2000, looking for UP and associated neurofibromas and neurofibroma-like neoplasms in persons younger than 18 years. RESULTS We identified a total of 27 patients suffering from UP, with 16 persons younger than 18 years. One 12-year-old Caucasian boy demonstrated multiple cutaneous mastocytomas consistent with the diagnosis of UP. On his trunk, four café-au-lait spots were found. A cutaneous neurofibroma was confirmed by skin biopsy. Magnetic resonance imaging detected multiple neoplasms located at the nerve roots of the spine, resembling plexiform neurofibromas. CONCLUSIONS There may be a concomitant appearance of UP and neoplasms, with mast cells possibly playing a causative role. The existence of neoplasms, including neurofibromas and neurofibroma-like lesions should be considered when examining UP cases.