Invasive cribriform carcinoma of the breast: a clinicopathological analysis of 12 cases with review of literature.

Invasive cribriform carcinoma (ICC) is a rare type of invasive breast cancer. We aim to investigate the clinicopathological features, immunophenotypes, diagnosis and differential diagnosis of ICC. Thus, clinicopathological data of 12 ICC patients were collected. All 12 cases were female, aged 38 to 75 years, with a median age of 53 years old. The maximum diameter of the tumor was 2 cm to 10 cm, in which the median tumor size was 2.54 cm in pure ICC and classical ICC. Microscopically, the cancer nests of ICC assumed an invasive, irregular island-shaped distribution, with an irregular mesh structure internally and fibrous reactions around most cancer nests. 67% (8/12) of cases were grade 1 and 33% (4/12) of cases were grade 2 tumors. Immunohistochemically, ER and PR were moderately to strongly positive with the positive tumor cell number accounting for 30% to 95% in all cases. HER-2 was negative in all cases except in one case which was positive (2+). Myoepithelial markers such as Calponin, p63, CK5/6 and CD10 were all negative in the cancer nests. 58% (7/12) of cases had a ki67 index of ≤ 14%. All follow-up patients were followed for 12 to 70 months (with a mean of 42 months), and were disease-free after treatment except for one patient whom we lost during the follow up. In conclusion, ICC, as a special type of breast cancer, has its unique clinicopathological and immunophenotypic characteristics, leading to a good prognosis.