乳腺导管小叶混合型癌3例临床病理观察

Mixed duct and lobular carcinoma of breast: a clinicopathological analysis of three cases

目的讨论3例乳腺导管小叶混合型癌的病理诊断,提高对该病的认识。方法采用常规HE染色及免疫组化SP染色获得正确诊断。结果乳腺导管小叶混合型癌具有两种不同类型的肿瘤形态,其中非特殊性浸润性导管癌区占肿瘤体积<49%,细胞具有多形性,排列呈实性癌巢、管状、条索状结构;浸润性小叶癌区细胞较小而一致,呈靶环状、列兵式排列特点,二者移行混合存在。免疫组化:ER、PR和c-erbB-2(2+),CK5(-),CK8(+);导管癌区E-cadherin(+),细胞膜p120(+);小叶癌区E-cadherin(-),34βE12(+),细胞质p120(+);Ki-67阳性指数>30%。结论乳腺导管小叶混合型癌是一种少见的乳腺异质性癌,以乳腺非特殊性浸润性导管癌和小叶癌混合存在为特征,易误诊为单纯的乳腺非特殊性浸润性导管癌或小叶癌,生物学行为更接近乳腺非特殊性导管癌。

Objective To explore the pathological diagnosis of mixed ductal and lobular carcinoma of the breast to improve the recognition of this lesion. Methods Conventional HE stain and immunohistochemistry （ S-P method） were used to make a correct diagnosis. Results The mixed ductal and lobular carcinoma presented two different patterns of morphological changes： invasive ductal carcinoma of not otherwise specified accounted for less than 49% of tumor, arranged in solid nests, tubular and trabecular structures with polymorphic tumor cells; invasive lobular carcinoma component had smaller and homogenous tumor cells, arranged in Indian-file or target-ring patterns. Both components were admixed and transited from one to another. Immunohistochemistry showed that the tumor cells of both components were positive for ER, PR, c-erbB-2 and CK8, but negative for CKS; ductal component was positive for E-cad and p120 （membranous）, but negative for 34βE12; lobular component was negative for E-cad and positive for p120 （cytoplasm） and 3413E12. Ki-67 index was more than 30%. Conclusions Mixed ductal and lobular carcinoma is a rare heterogeneous carcinoma of the breast, characterized by mixture of non-specific invasive ductal and lobular components. It is easily misdiagnosed as non-specific invasive ductal carcinoma or lobular carcinoma of the breast. The biological behaviors of this cancer are more close to that of the ductal carcinoma.