Incidence of Breast Cancer in Patients with Pure Flat Epithelial Atypia Diagnosed at Core-Needle Biopsy of the Breast

to determine the frequency of malignancy in subsequent breast excisions following core-needle biopsy (CNB) diagnosis of pure flat epithelial atypia (pFEA) and to evaluate the imaging features of the associated tumors. Retrospective review of 8,996 image-guided CNB (2002-2010) identified 115 cases of FEA not associated with other atypia. Patients with history of breast cancer or radiation therapy were excluded. One hundred four cases (women) with pFEA (mean age 51 years, range 29-77 years) were reviewed. Stereotactic CNB was performed in 79 (76 %) cases and ultrasound (US)-guided CNB in 25 (24 %) cases. In 99 cases 14G needles were used, and 10G vacuum-assisted devices were used in 5 cases. Ninety-four patients had subsequent excision. Ten patients declined excision, and imaging follow-up (mean of 36 months) is available. The upgrade rate of pFEA was defined as the number of patients diagnosed with invasive carcinoma (IC) or carcinoma in situ (CIS) divided by the total number of patients. 10 of 104 (9.6 %) patients were diagnosed with cancer: 9 presented as calcifications (89 % fine pleomorphic and amorphous) and 1 case as a mammographically occult mass. The size of calcifications was not statistically significant (P = 0.358). Five cases had ductal carcinoma in situ (DCIS) and five cases had IC (ductal and lobular) presenting as amorphous and pleomorphic calcifications. The upgrade rate of pFEA in our series was 9.6 %. The presence of 4.8 % of invasive cancers is substantial and warrants continuing management with surgical excision in all cases.