title: Mucinous cystadenocarcinoma of the breast with a basal-like immunophenotype.
abstract: Mucinous cystadenocarcinoma (MCA) of the breast is extremely rare and was only recently described as a distinct variant of invasive ductal carcinoma of the breast. A case of MCA is reported in a 41-year-old woman. Mammographic and ultrasonographic examinations showed an irregularly shaped 10.0 × 8.0 × 5.5 cm lesion with patching calcification in the upper outer quadrant of the left breast. The gross examination revealed that the tumor has a well-circumscribed edge with a gelatinous cut surface and hemorrhage and necrosis were also noticed in the mass. Microscopically, the mass resembled mucinous cystic neoplasm of the ovary and pancreas closely, with cystic areas lined by columnar mucinous cells and associated with abundant extracellular and intracellular mucin, which is distinctively different from mucinous carcinoma with typically nests of low grade neoplastic cells floating in the mucin pool. The tumor cells were positive for CK7, CK20 and CDX2 were negative and displayed a typical immunophenotype of basal-like breast cancer (ER, PR, HER2 were negative, CK5/6 and EGFR were positive). Metastatic carcinoma was identified in three of 14 axillary lymph nodes. We describe here a very unusual case of breast MCA with basal-like immunophenotype.
authors.affiliation: Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Yunte
authors.initials: Y
authors.lastname: Deng
authors.forename: Debin
authors.initials: D
authors.lastname: Xue
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Wang
authors.forename: Sanpeng
authors.initials: S
authors.lastname: Xu
authors.forename: Qilin
authors.initials: Q
authors.lastname: Ao
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Hu
authors.forename: Guoping
authors.initials: G
authors.lastname: Wang
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D002280:Basal Cell Carcinoma / Q000378:metabolism / Q000556:secondary*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000473:pathology; D018282:Cystadenocarcinoma, Mucinous / Q000378:metabolism / Q000556:secondary*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology; D008207:Lymphatic Metastasis; D008408:Mastectomy; D009367:Neoplasm Staging; D009378:Neoplasms, Multiple Primary
chemical_list: D014408:Biomarkers, Tumor