Ductal carcinoma in situ of the breast: correlation between mammographic calcification and tumor subtype.

OBJECTIVE. Histologic subtypes of ductal carcinoma in situ of the breast have been correlated with disease progression after local excision only. This study was undertaken to determine how the predominant type of calcification seen on mammography correlates with the predominant histologic tumor subtype, knowledge that could aid in the development of clinical criteria for selecting patients for appropriate local treatment. MATERIALS AND METHODS. A prospective double-blind study was performed to correlate the mammographic and histologic findings in 66 consecutive cases of ductal carcinoma in situ, or ductal carcinoma in situ associated with small invasive foci (n = 11), in which microcalcifications seen on mammograms were found in the ductal carcinoma during histologic evaluation of excisional biopsy specimens. Microcalcifications were categorized as predominantly linear or granular and were correlated with the predominant histologic subtype of ductal carcinoma in situ in the tissue containing the calcifications seen on mammograms. RESULTS. Predominantly linear calcifications were present in 47% (18/38) of ductal comedocarcinomas in situ compared with 18% (5/28) of cribriform, solid, or papillary subtypes (p = .01). Predominantly granular calcifications were present in 53% (20/38) of comedocarcinomas compared with 82% (23/28) of the noncomedo types (p = .01). In 94% (16/17) of cribriform ductal carcinomas in situ, granular microcalcifications were seen on mammograms. Seventy-eight percent (18/23) of linear calcifications in ductal carcinoma in situ were associated with the comedo subtype, whereas 53% (23/43) of the granular calcifications were associated with noncomedo subtypes. CONCLUSION. We conclude that the comedo subtype of ductal carcinoma in situ is more likely to be accompanied by linear calcifications than are the noncomedo subtypes, and noncomedo ductal carcinoma in situ is more likely to be associated with granular calcifications than is the comedo subtype when microcalcifications are seen on mammograms. However, there is considerable overlap, and the predominant histologic subtype cannot be predicted on the basis of the microcalcification type with a high degree of accuracy.