Fig. 3

Microphotograph of the patient’s thyroid ectopia in the left lung lobes. A Haematoxylin and eosin (H&E) staining showed that the pulmonary nodules consisted of typical thyroid tissue with follicles containing colloids (magnification × 40). B Immunohistochemistry staining of the follicular epithelial cells showed positivity for thyroglobulin (TG, magnification ×100). C Positive immunohistochemical staining for thyroid transcription factor-1 (TTF-1, magnification ×100). D Immunohistochemistry staining of follicular epithelial cells showed weak positivity for Ki67 (< 1%, magnification × 100)