Cytological diagnosis of Langerhans cell histiocytosis with cutaneous involvement

Langerhans cell histiocytosis (LCH) is a rare disease affecting predominantly children. The course of the disease varies, from spontaneous resolution to a progressive multisystem disorder with organ dysfunction and potential life-threatening complications. Diagnosis of LCH is often difficult and may be delayed because of its rarity and especially so if it occurs with unusual presentation. Fine needle aspiration cytology of a 4 year old male child, a case of LCH is presented with a purpose of highlighting the characteristic cytological features. A high index of suspicion, awareness of characteristic cytological features of LCH and its differential diagnoses is necessary. This can obviate the need of biopsy and electron microscopy. Immunohistochemistry if available can be performed on cytology smear and cell block.