Pregnancy-associated Breast Cancer: Why Breast Imaging During Pregnancy and Lactation Matters

Pregnancy-associated breast cancer is characterized as breast cancer diagnosed during pregnancy, within the first postpartum year, or during lactation. It usually presents as a palpable mass, although the large majority of palpable masses during pregnancy are benign. Breast cancer is the most common invasive malignancy diagnosed during pregnancy and lactation, and its incidence is increasing as more women delay childbearing. Understanding the appropriate methods for screening and diagnostic workup of breast findings in this population is imperative for radiologists to promptly diagnose pregnancy-associated breast cancer. Use of available imaging modalities should be tailored to patient-specific factors, with US typically the first-line modality due to patient age and decreased sensitivity of mammography in the setting of lactational changes. This article illustrates the spectrum of imaging appearances of pregnancy-associated breast cancer, the appropriate diagnostic imaging workup, and the unique challenges encountered in evaluation of this patient population.