An Unusual Presentation of Langerhans Cell Histiocytosis.

Langerhans cell histiocytosis (LCH) is a rare entity formerly known as eosinophilic granuloma. It is characterised by clonal multiplication of langerhans cells (LCs) that can occur anywhere in the body, especially in connective tissue of skin, lymph nodes and bone. Although rare, the disorder frequently affects children. A 7-year male child presented with the complaint of swelling at glabella. CT-scan revealed a defect in the middle of both frontal bones with brain herniating out of it. The clinical differential diagnosis included osteomyelitis, Tuberculosis and encephalocele. Fine needle aspiration cytology (FNAC) was performed and diagnosis of LCH was confirmed by typical cytological features, followed by immuno- histochemical staining for CD1a.