Plasma cell mastitis (PCM) is a chronic inflammatory disease of the breast. It is a benign entity mainly found in nonpregnant and nonlactating women. PCM presents with symptoms of inflammation, breast erythema, masses, and indurations. We herein describe a 26-year-old woman with a 2-year history of right breast swelling and a 1-year history of left breast swelling during pregnancy and lactation. She was clinically diagnosed with bilateral breast cancer, but a biopsy specimen revealed PCM. During pregnancy and lactation, PCM can present as bilateral lesions. Early presentation and diagnosis are crucial because PCM, a benign disease, can lead to remarkable morbidity if allowed to progress to an advanced stage.
Keywords: Plasma cell mastitis; benign; chronic inflammatory disease; lactation; nipple inversion/retraction; pregnancy.