Isolated Atypical Lobular Hyperplasia Diagnosed on Breast Biopsy: Low Upgrade Rate on Subsequent Excision With Long-Term Follow-up

- The upgrade rate to carcinoma on excision for atypical lobular hyperplasia diagnosed on breast biopsy is controversial.

- To review cases with isolated atypical lobular hyperplasia on biopsy to establish the rate of upgrade on excision and correlate with long-term follow-up.

- A database search was performed for 191 months to identify breast core biopsies with isolated atypical lobular hyperplasia. Cases with other atypical lesions in the biopsy or discordant radiologic-pathologic findings were excluded. Invasive carcinoma and ductal carcinoma in situ were considered upgraded pathology on excision. Patients without and with a history of, or concurrent diagnosis of, breast carcinoma were compared.

- Eighty-seven cases of isolated atypical lobular hyperplasia on biopsy underwent subsequent excision, which resulted in 3 upgraded cases (3.4%). All 3 cases with immediate upgrades revealed ductal carcinoma in situ. Upgrade was higher in patients with a concurrent diagnosis of breast carcinoma (2 of 26 and 1 of 61; 7.7% versus 1.6%, respectively). Follow-up information was available for 63 patients (57.8 ± 43.9 months; range, 6-183 months). Overall, 13% of patients without a history of breast carcinoma had a future breast cancer event, with the majority (83%) presenting in the contralateral breast.

- With careful radiologic-pathologic correlation, the upgrade rate for isolated atypical lobular hyperplasia on biopsy is low, and a more conservative approach may be appropriate.