Ductal carcinoma in situ that involves sclerosing adenosis: high frequency of bilateral breast cancer occurrence.

BACKGROUND: The radiologic and pathologic characteristics of ductal carcinoma in situ (DCIS) that involves sclerosing adenosis (SA) (SA DCIS) resemble those of invasive carcinoma. However, differences in the clinical features of these conditions remain unclear. This study was designed to clarify the clinicopathologic characteristics of SA DCIS compared with those of DCIS not involving SA (non,-SA DCIS).

METHODS: We retrospectively studied 1309 patients who underwent breast surgery at our hospital between January 2007 and December 2008. A total of 205 cases of DCIS were diagnosed in 198 patients, and 28 (13.7%) cases of breast SA DCIS were diagnosed in 24 patients. We compared clinical characteristics as well as radiologic and pathologic findings between SA DCIS and non-SA DCIS.

RESULTS: Synchronous and metachronous bilateral breast cancer was detected at a significantly higher rate in SA DCIS (9 [38%] of 24 patients) than in non-SA DCIS (22 [13%] of 174 patients; P < .01). As for radiologic findings, architectural distortion was more frequent in patients with SA DCIS than in those with non-SA DCIS (15 [54%] of 28 cases vs. 5 [2%] of 177 cases on mammography; P < .01; and 14 [50%] of 28 cases vs. 4 [2%] of 177 cases on ultrasound; P < .01). The rate of negativity for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 was significantly higher in SA DCIS than in non-SA DCIS (5 [18%] of 28 cases vs. 5 [3%] of 177 cases, P = .005) with immunohistochemical studies.

CONCLUSIONS: The rate of bilateral breast cancer and of architectural distortion on radiologic studies was higher in patients with SA DCIS than in those with non-SA DCIS. Our findings suggest that patients with SA DCIS should be closely monitored by radiologic and pathologic examinations to detect the presence of contralateral lesions.