Langerhans cell histiocytosis of thyroid-a diagnostic dilemma.

Langerhans cell histiocytosis (LCH) is a rare disease of antigen presenting cells and involvement of thyroid is really uncommon. The thyroid if involved is usually seen in multisystem disease but isolated thyroid involvement is very rare. The diagnosis of Langerhans cell histiocytosis of the thyroid is very challenging due to its rarity and is usually misdiagnosed as benign goiters, undifferentiated carcinoma, lymphoma, etc. Management of Langerhans cell histiocytosis of the thyroid also remains controversial. Prognosis in an isolated Langerhans cell histiocytosis of the thyroid is usually good but as it may precede a multisystem involvement, prolonged follow-up is required. We present a rare case of Langerhans cell histiocytosis of the thyroid, with variable diagnoses on fine needle aspiration cytology.