: Histiocytes with coffee bean like nucleus are the diagnostic hallmark of Langerhans cell histiocytosis (LCH) supported with immunohistochemical (IHC) demonstration of fascin, CD1a and S-100. We report a case of Letterer-Siwe disease in a 40year male diagnosed on cytology and IHC on cytosmears along with cytomorphology in Liquid based cytology (LBC) smears. Forty year male presented with complains of low grade fever and reduced appetite from two years with a cervical swelling and discomfort from five months. Fine needle aspiration(FNA) from cervical lymph node showed sheets of histiocytes in background of mixed inflammatory cells. LBC smears highlighted fine chromatin, delicate nuclear outline with coffee bean like morphology. On IHC tumor cells were positive for S-100 and CD1a. CT thorax revealed consolidation in left lower lung, bone lesions were found on skeletal survey. Hence diagnosis of Letterer-Siwe disease was given. Patient responded well to systemic chemotherapy.