Congenital self-healing histiocytosis (CSHH), and especially the solitary variant, is a rare primary skin disorder. We report on a newborn with a congenital solitary ulcerated skin nodule. Extracutaneous involvement was not found. A skin biopsy was performed at the age of 44 days and revealed a dense dermal infiltrate of large histiocytic cells. Immunohistochemical study revealed that the cells of the dermal infiltrate were Langerhans' cells which were strongly positive for S-100 and negative for lysozyme, leukocyte common antigen and alpha-1-antichymotrypsin. The skin lesion involuted spontaneously over the next month without any treatment. The clinical, histopathological and immunohistochemical results fulfilled the criteria of solitary CSHH. We herein report the first case of CSHH in Taiwan and the twelfth case of solitary CSHH in the world.
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