Radiological-pathological correlation in encapsulated papillary carcinoma of the breast

The study aims to investigate the radiological-pathological correlation in encapsulated papillary carcinoma (EPC) of the breast. We recruited patients with breast EPC between April 2016 and March 2025, and divided them into 3 histologic subtypes: pure EPC, EPC with ductal carcinoma in situ (DCIS), and EPC with invasive carcinoma (IC). Clinical, pathological, mammographic and ultrasonographic manifestations of the three histologic subtypes were analyzed. A total of 48 female patients with EPC were enrolled, with an average onset age of 62.2 ± 12.7 years. Histopathological analysis revealed 25 (52.1 %) pure EPC, 10 (20.8 %) EPC with DCIS, and 13 (27.1 %) EPC with IC. Immunohistochemistry indicated Luminal A predominated in pure EPC and EPC with IC, while Luminal B was more common in EPC with DCIS. The majority of mammography images showed high density or equal density masses with regular shape, and there were no significant differences in the size, morphology, margin, or internal calcification of tumors among the three histologic subtypes (P > 0.05). The majority of ultrasonography images of EPCs showed cystic and solid echogenicity masses with regular morphology and rich blood flow signals. There were no significant differences in the size, echo type, margin, posterior echo enhancement, or blood flow of tumors among the three histologic subtypes of EPC (P > 0.05), but the EPC with IC had a higher proportion of irregular morphology compared with pure EPC (P < 0.05). Therefore, mammography or ultrasonography alone is insufficient to distinguish the histologic subtypes of EPC, but irregular shape on ultrasonography should raise suspicion for non-pure EPC subtypes.