The risk of upgrade for atypical ductal hyperplasia detected on magnetic resonance imaging-guided biopsy: A study of 100 cases from four academic institutions

Aims: To identify variables that can predict upgrade for magnetic resonance imaging (MRI)-detected atypical ductal hyperplasia (ADH). Methods and results: We reviewed 1655 MRI-guided core biopsies between 2005 and 2013, yielding 100 (6%) cases with ADH. The pathological features of ADH and MRI findings were recorded. An upgrade was considered when the subsequent surgical excision yielded invasive carcinoma (IC) or ductal carcinoma in situ (DCIS). The rate of ADH between institutions was 3.3-7.1%, with an average of 6%. A total of 15 (15%) cases had upgrade, 12 DCIS and three IC. When all cases were included, only increased number of involved cores was statistically significant (P = 0.02). When cases with concurrent lobular neoplasia (LN) were excluded (n = 14), increased number of ADH foci and increased number of involved cores were statistically significant (P = 0.002, P = 0.009). We analysed the data separately from a single institution (n = 61). Increased number of foci, increased number of total cores and involved cores and larger ADH size predicted upgrade with statistical significance. Conclusions: The incidence of ADH in MRI-guided core biopsy is rare. The rate of upgrade is comparable to mammographically detected ADH, warranting surgical excision. Similar to mammographically detected lesions, the volume of the ADH predicts the upgrade.