Isolated Langerhans cell histiocytosis of the thyroid in a female infant.

Langerhans cell histiocytosis (LCH) involving the thyroid is very rare. It can be easily confused with far more common benign goiters or thyroid neoplasms. We report on a 5-month-old female patient presenting with progressive enlargement of an anterior neck mass. This patient underwent left subtotal thyroidectomy following which a diagnosis of isolated LCH involving the thyroid gland was confirmed. A course of chemotherapy was administered, and oral thyroxine replacement was initiated. Eighteen months after this treatment, the patient remained in complete remission. Following a thorough review of the literature, as best we are aware, this patient is the youngest individual suffering LCH who has been reported in the literature. In conclusion, isolated LCH of the thyroid is rare, and its diagnosis can be challenging for a clinician and typically requires appropriate awareness. Local excision is the treatment of choice, and prolonged follow-up is recommended.