Micropapillary carcinoma in breast cancer was first described by Petersen in 1993, after which other reports from all over the world described their characteristics. In Korea, this type of carcinoma was first described in 1996. The purpose of our study was to find the clinicopathological characteristics of micropapillary carcinomas from our experiences and to compare the results with those of other studies.

We analyzed 19 patients, from Dec. 1999 to Dec. 2002, diagnosed with micropapillary carcinomas from postoperative pathological reports retrospectively, compared with 939 patients diagnosed with infiltrating duct carcinoma in the same period.

The mean age and tumor size were 46.8 years (range 32~73) and 3.75cm (range 0.5~10.0), respectively. Micropapillary carcinoma showed the larger size (P=0.032) and more frequent rates of lymphovascular invasion (P=0.007) and metastasis to axillary lymph nodes (P=0.003) than infiltrating duct carcinoma. But, in the T stage-matched analysis, the rates of axillary lymph node metastasis in micropapillary carcinoma and infiltrating duct carcinoma showed no significant differences (T1, T2, T3 : P=0.072, P=0.080, P=0.575). Only in T2 stage, rates of lymphovascular invasion showed more frequent significantly in micropapillary carcinoma (P=0.012). Age, nuclear and histological grades showed no significant differences. The positive expressions of estrogen and progesterone receptors were more frequent in micropapillary carcinoma compared with infiltrating duct carcinoma, while the expressions of the C-erb-B2, p53, Ki-67 and bcl-2 showed no significant differences.

The micropapillary carcinomas showed more frequent lymphovascular invasion and positive expressions of the estrogen and progesterone receptors in their immunohistochemistry.