Five-year Study of Patients with Lactating Adenoma and Review of the Literature

Lactating adenoma is a benign breast mass related to physiological changes during pregnancy and increased estrogen level. Fibroadenoma and breast cancer should be considered in the differential diagnosis of this lesion. The purpose of this study was to report cases of lactating adenoma in Breast Cancer Research Center (BCRC) and review the relevant literature. All patients with histological diagnosis of lactating adenoma between April 2010 and December 2015 were selected. Patients’ data were extracted from their medical records and follow-up of the patients were done through in-person examination or rarely by telephone call. A total of 22 patients with pathological diagnosis of lactating adenoma were enrolled. The mean age of patients was 27±4.6 years. Fourteen patients were in breast-feeding period and eight were pregnant at the time of diagnosis. The chief complaint was breast mass in 16 patients and pain 6 patients. The mean size of masses was 4.1 cm (1.8-8 cm). For 13 patients, core needle biopsy (CNB) and for 6 patients open biopsy were performed and for the other 3 patients vacuum-assisted biopsy were done. In 5 patients, excisional biopsy was done in the follow-up period that one of them proved to be medullary carcinoma and other cases were benign. Lactating adenoma commonly presents as a palpable mass during the breastfeeding period or the third trimester of pregnancy. The most common ultrasonographic appearance is a hypoechoic mass with regular borders. It usually regresses after cessation of breastfeeding, however in patients with mass enlargement during the follow-up, period pathologic evaluation of the lesion through core needle biopsy should be performed to rule out coexistent carcinoma.