Abstract
Langerhans cell histiocytosis (LCH) involving the thyroid gland is extremely rare. Currently, the diagnosis and therapeutic evaluation for LCH involving thyroid is a challenge.We reported a rare case of LCH involving thyroid, presenting as painless thyroid goiters, and successfully performed positron emission tomography/computed tomography (PET/CT) to make an accurate diagnosis and therapeutic evaluation for LCH.Although the histology or cytology is the golden standard for the diagnosis of LCH involving thyroid, the PET/CT should be keep in mind when LCH involving thyroid with inconclusive cytologic results. During the treatment of LCH, PET/CT can be performed to assess the therapeutic effect and select the most effective and reliable treatment for LCH.