Fig. 3.

Pathological and immunohistochemical findings of the tumor. (a) The solid parts of the tumor showed that thyroid follicles containing colloid merge with ribbons of neoplastic cells in dense fibrous tissue stroma. Hematoxylin–eosin staining. Original magnification 200 ×. (b) The cystic components in the tumor were composed of single-layered mucinous epithelial cells. Hematoxylin–eosin staining. Original magnification 200 ×. (c) Carcinoid tumor cells showed positive staining for PYY. Methyl green counter-staining. Original magnification 200 ×.