Case for diagnosis. Adult-type xanthogranuloma.

Male patient, 28 years old, presented with an asymptomatic yellowish erythematous papule on his right thigh. Excisional biopsy was performed for histopathological examination of the lesion. Multinucleated cells (Touton giant cells) were observed. S100 immunohistochemistry was negative for CD1a and positive for CD4 and CD68. Based on clinical and histopathological findings associated with immunohistochemistry, we concluded that it was a case of adult-type xanthogranuloma. Because it was a solitary lesion without other clinical signs and symptoms, the medical conduct adopted was patient orientation.