Secretory carcinomas are well-circumscribed tumors with pushing borders. The central portion of the tumor usually contains hyalinized stroma as shown here. The peripheral portions are more cellular.
About the Disease
Secretory carcinoma of the breast is a rare tumor that was initially described in children but the majority of cases have been reported in adults. It displays microcystic, solid, tubular/glandular, and pseudopapillary growth patterns. The tumor cells have abundant pale eosinophilic or amphophilic granular or vacuolated cytoplasm. The glandular/microcystic spaces contain PAS+ve diastase-resistant eosinophilic secretions. It is positive for alpha-lactalbumin, mammaglobin, lysozyme, S-100 protein and cytokeratins CK5/6 and CK8/18 with variable expression of CEA and GCDFP-15. They are usually negative for ER, PR, and HER2 and have a low Ki-67 labeling index. Secretory carcinoma of breast may be related to acinic cell carcinoma of salivary glands. A similar molecular genetic abnormality has been found in both tumors - a recurrent balanced chromosomal translocation, t(12;15)(p13;q25), which leads to the formation of ETV6-NTRK3 fusion gene. It is a relatively indolent tumor with an excellent overall prognosis.