Secretory Carcinoma of Breast : Immunohistochemistry
A focus of tubular/ductular growth pattern in a secretory carcinoma of breast. The lumens contain abundant dense eosinophilic secretions that are PAS+ve and diastase-resistant. The nuclei are vesicular and uniform, round to oval with prominent nucleoli. Mitotic figures are rare. Immunohistochemistry:Secretory carcinomas of breast are positive for alpha-lactalbumin, mammaglobin, lysozyme and S-100 protein. They show variable expression of CEA and GCDFP-15. Immunoreactivity for cytokeratins CK5/6 and CK8/18 has also been reported. They are usually negative for ER, PR, and HER2 and have a low Ki-67 labeling index.