Langerhans Cell Histiocytosis in a Five-Month-Old Infant

reaction from metaphysis or diaphysis in the proximal phalanx of the right middle finger (Figure 2). Fine needle aspiration cytology was performed suggestive of an inflamed granulation tissue with atypical cells displaying irregular nuclei and ample cytoplasm. Immunohistochemical study of the atypical cells showed positive staining of CD1a, CD5, CD68 (KP1), Langerin, S-100 protein, and negative staining of CD20. The findings confirmed the diagnosis of Langerhans cell histiocytosis. The patient did not receive any treatment, but routine follow-up. One year later, the patient was asymptomatic and in good health.