Abstract

Langerhans cell histiocytosis (LCH) is a pleomorphic disease entity characterized by local or disseminated atypical Langerhans cells (LCs) found most commonly in bone, lungs, mucocutaneous structures and endocrine organs. Among different sites, unifocal disease confined to a lymph node (LN) is rare. We report a case of LCH confined to a LN in a 38-year-old male who presented with a 2 cm-sized cervical mass. The fine needle aspiration (FNA) smears of cervical LN showed high cellularity having isolated LCs with contorted nuclei and nuclear grooves mixed in multinucleated giant cells, small lymphocytes and eosinophils. Charcot-Leyden crystals were also seen, as were a few dendritic-like cells and intranuclear inclusions. Confirmation of LCH was made by histopathologic studies, positive reactions for S-100 protein and CD1a immunohistochemical staining and by the demonstration of Birbeck granules on electron microscopy. The differentials to be considered include dermatopathic lymphadenitis, sinus histiocytosis with massive lymphadenopathy, Hodgkin's lymphoma and malignant histiocytosis. The characteristic cytomorphologic pattern of LCH in a LN FNA smear plays an important role in suggesting the diagnosis of LCH.

• Keywords: Langerhans cell histiocytosis;Lymph node;Aspiration cytology