MR imaging characteristics of breast cancer diagnosed during lactation

To describe the MR imaging characteristics of breast cancer diagnosed during lactation and evaluate the usefulness of MR imaging.

The MR images of nine patients (age range, 29-37 years) with pathologically confirmed breast carcinoma during lactation were evaluated retrospectively. Background parenchymal enhancement of the lactating mammary tissue was determined. The images were reviewed for evaluation of lesion detection, enhancement type (mass/non-mass), shape, margin, contrast enhancement and time-intensity curve pattern in the dynamic study. The breast MR images after neoadjuvant chemotherapy were also reviewed.

Although the breasts showed marked (n = 7) or moderate (n = 2) background parenchymal enhancement, MR imaging depicted breast cancer in all patients. All nine tumours were visible as masses. The most common shape and margin of the masses were an irregular mass (n = 5) with an irregular margin (n = 9). Contrast enhancement was heterogeneous or rim enhancement. The predominant kinetic pattern was rapid increase (n = 9) in the initial phase and washout (n = 5) in the delayed phase. Additional sites of cancer other than the index lesion were detected with MR imaging in three patients (33.3%). MR imaging demonstrated partial response in five of six patients who were evaluated for response to chemotherapy.

All breast cancers in lactating females in this study were observed on breast MR imaging despite the moderate-to-marked background parenchymal enhancement of lactating mammary tissue. Advances in knowledge: MR imaging can be used in the evaluation of disease extent and assessment of therapeutic response after neoadjuvant chemotherapy of breast cancer diagnosed during lactation.