目的 探讨乳腺包裹性乳头状癌（encapsulated papillary carcinoma，EPC）的临床病理特征和免疫表型特点。方法 回顾性分析31例EPC患者的临床资料、随访结果及组织病理学、免疫组织化学（免疫组化）染色的特征[（包括P63、CK5/6、钙调蛋白（Calponin）、雌激素受体(estrogen receptor, ER)、孕激素受体（progestogen receptor, PR）、人表皮生长因子受体2（human epidermal growth factor receptor 2，HER2）、Ki-67）]。结果 31例EPC患者均为女性，发病年龄为34~83岁，平均年龄为63岁，最常见的临床症状为乳腺肿块和乳头溢液，肿瘤的最大径为0.8~6.5 cm（平均为3 cm）。光学显微镜低倍镜下，肿瘤多为单发扩张的囊腔，可见明显的纤维性厚包膜，包裹的结节由纤维血管细乳头构成，乳头表面衬覆核呈低至中级别的单一型肿瘤性上皮细胞，细胞通常排列成实性或筛状。免疫组化染色示，肿瘤细胞呈ER、PR弥漫阳性， Ki-67阳性指数低于<10%，HER2及P63、CK5/6、Calponin等肌上皮标志的表达均为阴性。随访病例均无局部复发、远处转移和死亡。结论 EPC好发于老年妇女，患者预后良好，肿瘤细胞呈实性或筛状的乳头状排列，且有厚纤维包膜的病理组织形态，免疫组化检测呈ER、PR弥漫阳性，P63、CK5/6和Calponin等肌上皮标志阴性，根据这些特征可进行EPC的病理诊断，并为临床确定合理的治疗方案提供依据。

Objective: To analyze the clinical-pathological features, treatment and prognosis of encapsulated papillary carcinoma (EPC) of breast. Methods: Thirty-one cases with EPC were enrolled. Clinical symptoms and pathological characteristics were retrospectively analyzed. The immunohistochemical staining included P63, CK5/6, Calponin, ER, PR, HER2, Ki67. Results: All of the cases were woman with a mean age of 63 years old, ranging from 34 to 83 years old. Palpable mass and nipple discharge were the most common symptoms. The mass ranged in size from 0.8-6.5 cm (mean 3 cm). Microscopic examination showed that majority of the EPCs were single lesion. A thick fibrous capsule is evident under low-power examination. The nodule surrounded by capsule was composed of delicate fibrovascular stalks, covered with a monomorphic population of neoplastic epithelial cells with low-or intermediate-grade nuclei. The epithelial cells were typically arranged in either solid or cribriform pattern. The tumor cells were positive for ER and PR, but were HER2 negative; P63, CK5/6 and Calponin were negative. The positive percentage for Ki67 was under 10%. Conclusions: EPC is a breast tumor with good prognosis generally found in elderly women. The tumor cells are typically arranged in either solid or cribriform pattern and diffusely positive for ER and PR, but HER2 was negative. Myoepithelial cell markers including P63, CK5/6 and Calponin were negative. The positive percentage for Ki67 is under 10%. The EPC is diagnosed according to these characteristics, which are helpful for the designing of reasonable treatment.