Pure flat epithelial atypia identified on core needle biopsy does not require excision

Routine excision of flat epithelial atypia (FEA) of the breast found on core needle biopsy (CNB) is being questioned and a policy of selective excision of FEA was adopted in our area. The purpose of this study was to evaluate the upstage rate to malignancy across multiple diagnostic centers in our area following the policy of selective excision and to identify factors predictive of malignancy.

Patients having excision of CNB FEA at our regional Hospital between 2013 and 2017 were identified. The primary endpoint was upstage to malignancy after excision. We also assessed for clinical, radiological, and pathological features associated with malignancy.

We identified 187 patients. Eighty-nine had pure FEA, 71 had concurrent ADH, and 18 had other pathological lesions. Following surgical excision, 9 patients were upstaged to malignancy (4. 8%) with 8 having concurrent ADH (2 invasive ductal carcinoma, 6 DCIS) and 1 with concurrent Complex Sclerosing Lesion (DCIS). None of the pure FEA cases upstaged. The presence of ADH or CSL in the CNB were the only factors found to be predictive of upstaging (p = 0.001, p = 0.0001 respectively).

The upstage rate to malignancy after excision of pure FEA at out center is 0%. Therefore, we recommend that pure FEA with radiology and pathology concordance does not require surgical excision and can instead be followed with serial imaging. However, patients with FEA in association with other high-risk lesions should be managed as per indicated for the other high-risk lesion and FEA with ADH should be excised.