28 March 2026
: Case report 
Hormone Receptor–Positive Encapsulated Papillary Carcinoma of the Breast With High-Grade Cytological Features: A Case Report With Invasive Heterogeneity
Challenging differential diagnosis, Diagnostic / therapeutic accidents, Unusual setting of medical care, Rare coexistence of disease or pathology
Yao Liu ABCDEF 1,2,3, Akihiro Shioya
ABCD 1,3*, Yusuke Haba BF 4, Masafumi Inokuchi BF 4, Sohsuke Yamada AD 1,3
DOI: 10.12659/AJCR.951744
Am J Case Rep 2026; 27:e951744
Figure 3 Immunophenotype features of the tumor (immunohistochemical staining). (A–C) The tumor cells of encapsulated papillary carcinoma (EPC) with high-grade features, high-grade invasive component, and low-grade invasive component were positive for estrogen receptor. (D–F) The tumor cells of EPC with high-grade features, high-grade invasive component and low-grade invasive component were positive for progesterone receptor. (G–I) The tumor cells of EPC with high-grade features, high-grade invasive component and low-grade invasive component were negative for HER2 (1+). (J–L) The Ki-67 proliferation index of EPC with high-grade features, high-grade invasive component tumor cells, and low-grade invasive component tumor cells were 46.5%, 36.5%, and 5%, respectively. The red box indicates the hotspot area (amplification: A–I, 400×; J–L, 200×).