[Secretory carcinoma of the breast: clinical histopathologic and biological behaviors].

Objective: To investigate the clinicopathological and immunohistochemistrical features of secretory carcinoma of the breast (SCB), as well as its diagnosis and prognosis. Methods: Five cases of SCB were collected and specimens were fully drawn. Microscopic pathology examinations and immunohistochemistry(SP method)were performed. Results: Five cases were all female patients aged from 31 to 54 years old (with an average age of 38 years), and all patients initially presented with the painless breast lump, often near the areola. Macroscopically, all the tumors were relatively circumscribed, with a mean diameter of 2.1 cm(1.2-3.0 cm). Histologically, the tumors revealed different patterns (microcystic, solid, ductal, and so forth) and appeared large amounts of intracellular and extracellular eosinophilic PAS- and AB-PAS- positive secretory materials, as well as the granular eosinophilic cytoplasm. Immunohistochemistrically, the tumor cells were strongly positive for epithelial membrane antigen (EMA) and S-100. Three cases had negative expression for estrogen receptor (ER) and progesterone (PR), and two cases had weakly focal expression. Human epidermal growth factor receptor 2 (HER2) and P53 were negative, while only one case had weakly focal expression. The tumors were positive for CK7, CK5/6, CD10, but they were negative for CEA, smooth muscle actin (SMA) and P63 . The proliferation index of Ki-67 was 5%-8%. There was no patient with metastasis of the tumor in axillary lymph node. Except 1 case lost follow-up, and the rest had no recurrence or distant metastasis. Conclusions: SCB is very rare, with low malignancy, and has better prognosis, but it is usually classified as triple-negative breast cancer because of the immune phenotype. The correct diagnosis of this lesion depends on clinical characteristics, morphology and immunohistochemistry.