Fig. 2

Core needle biopsy histological findings of the tumor (a) and (b) HE-stained sections at × 4 and × 20 magnification. a Low-power view illustrates a solid papillary carcinoma. b High-power view demonstrates the rosette structure of a solid papillary growth pattern and a network of thick fibrovascular cores among proliferating atypical malignant cells. c Positive immunohistochemical staining findings for the estrogen receptor. Positive immunohistochemical staining findings for the following markers demonstrate the neuroendocrine component of the tumor: d neuron-specific enolase, e chromogranin, and f synaptophysin. g Negative immunohistochemical staining for the myoepithelial marker p63 (a: × 4, b–g: × 20)