Objective  To analyze the clinical characteristics of thyroid LCH to enhance understanding of the disease.  Methods  We retrospectively studied the clinical data from six thyroid LCH patients who hospitalized in Huashan Hospital Affiliated to Fudan University from January 2015 to January 2022.We analyzed the ultrasound and ¹⁸F FDG-PET/CT imaging characteristics of thyroid LCH.  Results  The six patients diagnosed (2 males and 4 females) were between 18 and 58 years old.All patients had diabetes insipidus.MRI revealed thickened pituitary stalk.Two cases had central hypothyroidism, while four cases euthyroidism.Three cases tested positive for thyroid antibodies.Ultrasound showed thyroid nodules of TI-RADS 3 in three cases, TI-RADS 4 in two cases, and 1 with nodular goiter.Ultrasound showed that all sic cases indicated low echogenicity, 5 of which clear boundaries, 4 of which uneven echo distribution, 5 of which irregular shape, and noen has calcification.¹⁸F FDG-PET/CT indicated high uptake nodules with SUVmax values all above 10.4 cases were diagnosed by surgical excision and the other 2 by coarse-needle aspiration biopsy.When diagnosed, two cases had liver and thymus involvement respectively.One case had lung and bone involvement respectively.After treatment, 4 cases showed that nodular goiter shrank, while the other two with liver involvement progressed fast and no assessment made.  Conclusions  Thyroid LCH presented low echogenicity, clear boundaries, irregular shape, without calcification, and high uptake in ¹⁸F FDG-PET/CT.A definite diagnosis of pituitary stalk thicking accompanied by thyroid nodules, especially those with hypoechoic and irregular nodules, can be achieved by coarse-needle aspiration biopsy and langerin-specific pathological staining.