Cutaneous Langerhans cell histiocytosis presenting in a neonate

A newborn boy presented at birth with a firm erythematous nodule, measuring 25×18 mm on the medial aspect of his left shin below the knee (figure 1). The lesion had a depressed centre covered with a crust and subtle telangiectasia on the edges. The rest of the examination was normal. He had been born at term following an uncomplicated pregnancy. Figure 1 Erythematous nodule measuring 25×18 mm on the medial aspect left shin. A 4 mm punch biopsy of the lesion was performed, revealing S100 …