Pagetoid self-healing Langerhans cell histiocytosis in an infant

We report Langerhans cell (LC) histiocytosis in a male infant who developed numerous papular lesions on the trunk and posterior scalp soon after birth and spontaneously recovered from the disease within 7 months. Histological ly S-100-positive cells were detected in the epidermis and papillary dermis , in some lesions mostly in the epidermis. Tumor cells in the epidermis wer e either clustered, forming nests, or scattered singly in pagetoid fashion. Electron microscopy confirmed the presence of Birbeck granules in these ce lls, They exhibited many interesting features usually not found in normal L Cs, including mitosis, frequent apoptosis, Birbeck granules invaginated in the nucleus, autophagocytosis of Birbeck granules, and active ingestion of extracellular material through Birbeck granules attached to cell membranes, It is suggested that either a strong epidermotropism of tumor cells or a p roliferation of the resident LCs of the epidermis is responsible for this i ntraepidermal growth pattern. Cellular necrosis through very active apoptos is and the superficial nature of the growth might have contributed to the s elf-healing course in this patient.