Is the appearance of microcalcifications on mammography useful in predicting histological grade of malignancy in ductal cancer in situ?

It has been proposed that the grade of malignancy of ductal carcinoma in situ (DCIS) of the breast can be estimated by the morphology of microcalcifications found on mammography. We correlated microcalcifications and histopathology in a retrospective blinded review. We reviewed all patients who underwent excisional breast biopsy over a 5 1/2-year period. Mammograms and pathology slides of all patients (n = 49) with DCIS of the breast were included in a blinded retrospective analysis. Mammographic microcalcifications were divided into four categories, "linear branching", "coarse granular", "fine granular" or "no microcalcification". Independently, pathology specimens were assigned to poorly, intermediately and well differentiated categories according to the consensus classification of DCIS introduced by the European Organisation for the Research and Treatment of Cancer. Two patients had no microcalcifications. 25 (53%) of the remaining 47 patients had "linear branching" microcalcifications, 10 (21%) had "coarse granular" and 12 (25.5%) had "fine granular" microcalcifications. 19 patients (40%) had poorly differentiated, 23 (49%) intermediately differentiated and 5 (11%) well differentiated subtypes of DCIS. 14 (56%) of the 25 patients with "linear branching" microcalcifications had poorly differentiated DCIS, 10 (40%) had intermediately differentiated and 1 (4%) had well differentiated DCIS. 3 (30%) of 10 patients with "coarse granular" microcalcifications had poorly differentiated DCIS, 5 (50%) had intermediately differentiated and 2 (20%) had well differentiated DCIS. 2 (17%) of 12 patients with "fine granular" microcalcifications had poorly differentiated DCIS, 8 (67%) had intermediately differentiated and 2 (17%) had well differentiated DCIS. These findings were not statistically significant. In conclusion, "linear branching" microcalcifications tended to be associated with higher pathological grading. However, correlation was poor and there was considerable overlap between categories. Histological type of DCIS cannot be predicted prospectively on mammographic appearances.