CD1A and Langerhans cell histiocytosis: 18F-FDG PET/CT can also provide benefits in investigating other organ involvements.13 Because histopathological features may interfere with other diseases, CD1a and S100 positivity should be seen for a definite diagnosis.5,14 In some publications, it is stated that CD207 (Langerin) immunohistochemical staining will also help in the accurate diagnosis of LCH.14 When primary thyroid LCH is diagnosed, it is recommended to perform some tests, such as thoracic CT, bone scintigraphy, and abdominal USG, to determine the presence of multisystem involvement.3,6