Acanthosis nigricans (AN) is a disorder often accompanied by internal malignancy in adult patients, but in children it is usually benign. Generalized forms of AN, especially in childhood, are extremely rare. We report a 5-year-old boy with a 3-year history of AN who had generalized roughness and hyperpigmentation, numerous skin wrinkles, disseminated skin tags, tripe palms, and intensive pruritus. No clinical evidence of internal disorders, notably of an endocrinologic or neoplastic nature, have been detected thus far.

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BackgroundDipeptidyl peptidase IV, a multifunctional serine protease, is implicated in regulation of malignant transformation, promotion and further progression of cancer, exerting tumor-suppressing or even completely opposite - tumor-promoting activities.The aim of present research was to determine the serum DPPIV activity, as well as the percentages of CD26+ lymphocytes, CD26+ overall white blood cells and the mean fluorescence intensity of CD26 expression on lymphocytes in patients with melanoma, people with vitiligo and in healthy controls.MethodsThe activity of DPPIV in serum was determined by colorimetric test. Expression of DPPIV (as CD26) on immunocompetent peripheral white blood cells was done using flow cytometry analysis.ResultsData from our study show for the first time statistically significant decrease: in the serum DPPIV activity, in the percentage of CD26+ overall white blood cells and in the percentage of lymphocytes in patients with melanoma in comparison to healthy control people. In addition, significantly lower serum DPPIV activity was found in the group of patients with melanoma in relation to people with vitiligo too.ConclusionThis study indicates the need for exploring the cause and the importance of the disturbances in the serum DPPIV activity and in the CD26 expression on immunocompetent cells in complex molecular mechanisms underlying the development and progression of melanoma.

The increases in the size of melanocytic naevi that we found 28 days after cessation of intense sun exposure are probably induced by UV radiation, whereas changes in DELM features that were not reversible in some small naevi at the 1-year follow-up could be related both to sun exposure and to the natural evolution of the naevi. The use of sunscreen does not seem to prevent these changes. Small naevi in low-risk young and middle-aged patients seem to be more prone to sun-induced DELM changes.