Langerhans cell histiocytosis involving the thyroid and parathyroid glands

Langerhans cell histiocytosis (LCH) is a rare illness, and the disease affl icting the thyroid gland is very uncommon, even in the presence of multisys tem involvement. In this report, we document histologically, for the first time, concurrent involvement of the thyroid and parathyroid glands by LCH. A young Chinese woman with a history of diabetes insipidus and hypogonadism underwent a total thyroidectomy for enlarged thyroid gland secondary to LC H causing airway obstruction. Microscopic examination of the excised specim en disclosed CD1a- and S-100-positive LCH cells involving the thyroid and p arathyroid glands. In a patient with LCH affecting the thyroid gland, parat hyroid gland disease should be suspected when the serum calcium levels are depressed in association with an inappropriate serum parathyroid hormone le vel, such as a normal parathyroid hormone level in this case.