Fig. 3.

Core needle biopsy findings of a follicular neoplasm with a macrofollicular growth pattern. The images in the left column and the right column show the core needle biopsy specimen and the resected specimen, respectively. (A) The ultrasound image shows a well-circumscribed, isoechoic, ovoid nodule with a peripheral hypoechoic rim. A focal cystic change is present. (B) The surgical specimen exhibits a thick fibrotic capsule surrounding the nodule. (C) The core needle biopsy shows a macrofollicular proliferative lesion with a fibrous capsule (arrows). (E) The high-power view of the biopsy specimen shows benign-appearing follicular cells. The typical ultrasound features and thick fibrous capsule can lead to a diagnosis of follicular neoplasm, even in a macrofollicular lesion. The microscopic examination of the surgical specimen shows that the tumor is well encapsulated (D) and capsular invasion is minimal (F).