摘要目的 探讨乳腺表现为扩张性侵袭的乳头状癌的病理形态学、诊断及鉴别诊断.方法 应用光镜观察、免疫组织化学MaxVision两步法染色等对25例乳腺表现为扩张性侵袭的乳头状癌进行分析.结果 25例患者均为女性,年龄26 ～ 84岁(中位年龄69岁),肿瘤直径1～5 cm(2例分别为4 cm和5 cm,其余23例均＜2.5 cm).肿物大体实性、边界清楚,镜下缺乏明确包膜,部分病例有纤维带与周围乳腺组织分隔.癌组织的基本结构为分枝乳头状,乳头纤细或钝圆,具有纤维血管轴心.乳头互相融合成不规则腺样、筛网状,还互相融合形成体积巨大的复杂乳头、网状乳头状结构,这是该组病例的共同显著特点.其中3例在形似导管内癌的腺腔内,乳头的轴心逐渐消失,形成实性细胞条索或散落细胞团,类似微乳头型导管内癌.细胞呈单层、假复层或复层,立方状-低柱状-高柱状,胞质嗜酸性或淡染,排列整齐或杂乱.细胞核通常具有轻-中度异型性与多形性,核分裂象较少.1例伴明显鳞状上皮化生,4例可见大汗腺样顶浆分泌胞突.2例癌细胞具有两种明显不同的形态特点,类似于双态性导管内乳头状癌.1例癌细胞胞质嗜酸性较强；1例胞质呈嗜酸性颗粒状,核仁较明显,具有大汗腺形态特点.肿瘤内间质较少,多为纤细的硬化性纤维间质,有时亦可有多少不等的炎性细胞浸润或含铁血黄素沉积.免疫组织化学染色,25例均缺乏平滑肌肌动蛋白、p63、CD10、CK5/6的肌上皮表达；在7例进行雌激素受体(ER)、孕激素受体(PR)、HER2染色的病例中,5例ER、PR阳性率高于75％,1例ER、PR阳性率约45％,此6例HER2均阴性；伴鳞状上皮化生的1例ER、PR阴性,HER2染色评分2+(但未经荧光原位杂交证实是否存在基因扩增).9例进行腋窝淋巴结清扫的病例,有2例发生转移.结论 乳头状癌是乳腺病理诊断的难点,当形态学上出现乳头互相融合形成体积较大的复杂乳头或筛状结构、且肌上皮免疫组织化学染色完全缺失时,应当考虑存在扩张性侵袭的可能.

abstractsObjective To study the pathology,diagnosis and differential diagnosis of papillary carcinoma of the breast featuring expansile invasion.Methods Morphologic analysis and immunohistochemical study using MaxVision method were carried out in 25 cases of papillary carcinoma of the breast featuring expansile type of invasion.Results All the 25 cases were female,and ranged from 26 to 84 years old in age with median of 69.The diameters of the neoplasms were from 1 cm to 5 cm,among which those of two cases were 4 cm and 5 cm respectively and the others were less than 2.5 cm.The tumor appeared solid and well-demarcated on gross examination.Histologically,the tumor was non-encapsulated.In some cases,the tumor tissue was separated by fibrous septa or intervening native breast tissue.The tumor was composed of arborizing papillae with fibrovascular cores,associated glandular fusion and cribriform pattern.The fibrovascular cores were covered by cuboidal to columnar cells.In 3 of the cases studied,focal transition with micropapillary ductal carcinoma-in-situ was demonstrated.The tumor cells showed mild or moderate degree of nuclear pleomorphism and contained amphophilic to eosinophilic cytoplasm.Mitotic figures were not frequently seen.One case displayed squamoos metaplasia and 4 cases showed apocrine metaplasia.Dimorphic features were identified in 2 cases.The stromal tissue within the tumor was often scanty and sometimes sclerotic,associated with various degrees of inflammatory infiltrate and hemosiderin deposition.Immunohistochemical study for smooth muscle actin,p63,CD10 and CK5/6 showed negative staining in all of the 25 cases studied,including the 2 cases with dimorphic features.Seven cases had breast cancer marker study performed.Six cases were positive for estrogen receptor and progesterone receptor.HER2 oncoprotein was not over-expressed in 6 cases.Nine patients underwent axillary dissection and 2 of them showed axillary nodal metastasis.Conclusions Diagnosis of papillary carcinoma of the breast is one of the most difficult areas in breast pathology.Demonstration of expansile type of invasion,when coupled with complex papillary fusion,cribriform pattern and absence of myoepithelial cells on immunohistochemistry,is helpful in arriving at a correct diagnosis.