Langerhans Cell Histiocytosis-A Benign Presentation Heralding a Serious Disease

A 3-year old White boy was referred to our dermatology department with a papular disseminated eruption, evolving for 7 months. Several topical antibiotics and corticosteroids were used without improvement. The dermatosis was locally asymptomatic, and systemic symptoms were absent. Examination revealed multiple, skin-colored to pinkish monomorphic papules with a generalized distribution involving the face, trunk, and limbs (Figure 1). The lesions spared the scalp, palms, and soles. Cervical, axillary, and inguinal lymphatic nodes were not palpable. Cutaneous biopsy of one of the abdominal lesions revealed an unremarkable epidermis but a reticular dermis with clusters of histiocytic, lymphocytic, and rare eosinophil cells. In the immunohistochemical study, expression of CD1a was observed in the histiocytic cells and S100 in the antigen-presenting cells of the dermal infiltrate (Figures 2 and 3). Taking into account the clinical presentation and the histopathologic result, a diagnosis of Langerhans cell histiocytosis (LCH) was established.