[Diagnostic value of café-au-lait spots (author's transl)].

Clinical, histological and ultrastructural studies of café-au-lait spots (C. L. S.) are summarized, in order to establish a differential diagnosis between isolated C. L. S. and C. L. S. associated with polymalformative syndromes. The differential of C. L. S. include nevus spilus and Becker's melanosis. Distinctive clinical and histological features usually differentiate these entities. The incidence of C. L. S. in the general population is about 10 p. 100. It is significantly increased in neurofibromatosis (90 to 100 p. 100), Albright's syndrome (35 p. 100), ataxia telangiectasia (20 p. 100), Silver-Russel syndrome (45 p. 100), Watson's syndrome (60 p. 100), Léopard syndrome (38 p. 100) and Fanconi's anemia. An increased incidence of C. L. S. has been reported in tuberous sclerosis. C. L. S. have been observed in isolated patients with bony skeletal and muscular abnormalities, in Westerhof's syndrome, Leschke's syndrome, Cowden's disease, nevoid basal cell carcinoma syndrome, epidermal nevus syndrome, Gaucher's disease, Hunter's disease, Turner syndrome. Several clinical features of C. L. S. (number, size, distribution, family history) allow to distinguish isolated C. L. S. from C. L. S. associated with polymalformative syndromes. However, the distinction between "normal" and "abnormal" is not always clear cut. A study on the cellular and subcellular characterization of C. L. S. in a case of neurofibromatosis, tuberous sclerosis, Albright's syndrome and ataxia telangiectasia is reported. In each case, the number of epidermal melanocytes, the size of melanosomes and their mode of distribution within epidermal keratinocytes were evaluated. The authors emphasize that no specific histological or ultrastructural "marker" can be helpful for the differential diagnosis between the various forms of C. L. S. (C. L. S. of neurofibromatosis, Albright...).