Do All Cases of Ductal Carcinoma in Situ Have Similar Imaging Appearances?

The objective of a recent study was to perform a retrospective review of mammographic, sonographic, and pathologic features of symptomatic and screening-detected DCIS.

The study has concluded that sonographic appearances of incidental ductal carcinoma in situ (DCIS) and symptomatic ductal carcinoma in situ are variable.

Methodology
The study included 106 DCIS lesions detected on screening mammography and 125 DCIS lesions detected on diagnostic mammography from a single academic institution. Preoperative whole-breast sonography results, mammography results, and pathologic results were reviewed.

Results of the Study
The majority of patients with symptomatic DCIS presented with palpable masses. Patients with screening-detected DCIS were significantly older than those with symptomatic DCIS. On sonography, masses were the most common features of DCIS for both groups.

However, masses were identified in 92% of symptomatic DCIS cases, which was significantly higher than that of screening-detected DCIS. The majority of symptomatic and screening-detected DCIS showed irregular shapes with indistinct or microlobulated margins on ultrasonography.

Screening-detected DCISs were more often isoechoic or hypoechoic, whereas symptomatic DCISs more often showed mixed echogenicity or complex cystic appearance.

Symptomatic DCISs were more frequently associated with posterior acoustic enhancement and ductal changes. Screening-detected DCISs were more commonly associated with posterior shadowing and clustered microcalcifications. Although 99% of symptomatic DCISs were identified on ultrasonography, the false-negative rate of symptomatic DCIS on mammography was 24%.

On mammography, microcalcifications were more often seen among screening-detected DCIS, and masses were more commonly seen with symptomatic DCIS. The false-negative rate of mammography was significantly higher with symptomatic DCIS. On histology, symptomatic DCIS was significantly larger than screening-detected DCIS.

However, there were no significant differences in nuclear grade, presence of micro invasion, or hormonal receptor status between groups.

Conclusions
DCIS detected on screening and diagnostic mammography has different sonographic appearances.

Reviewer’s Comments
DCIS represents approximately one third of screening-detected breast cancers and 5% of breast cancers in symptomatic patients. Although mammography offers high sensitivity in detecting DCIS when manifested as microcalcifications, approximately 6% to 23% of DCIS cases are mammographically occult.

The results of this study showed 99% sensitivity of detecting symptomatic DCIS and 90% sensitivity of detecting screening-detected DCIS by whole-breast ultrasonography technique. Therefore, radiologists should consider using whole-breast ultrasonography as an adjuvant tool, and they must be aware of different sonographic appearances of symptomatic and screening-detected DCIS while reviewing sonographic images.

Author: Bokran Won, MD

Reference
Shin HJ, Kim HH, et al. Screening-Detected and Symptomatic Ductal Carcinoma In Situ: Differences in the Sonographic and Pathologic Features.
AJR Am J Roentgenol; 2008; 190 (February): 516-525.