This report detailed a case of granulomatous mastitis during pregnancy. At 25 +1 weeks of gestation, the patient presented with a 3 cm indurated mass in the upper outer quadrant of the right breast, exhibiting needle-like pain, tenderness, erythema, edema, and elevated skin temperature. Ultrasound at 26 +1 weeks of gestation revealed an 8.0 cm×2.4 cm×9.0 cm heterogeneous hypoechoic area (BI-RADS category 4B), suggestive of inflammation. Aspiration and biopsy at 27 +3 weeks of gestation confirmed granulomatous lobular mastitis. Surgical incision and drainage under general anesthesia were performed at 29 +1 weeks of gestation, and intraoperative cultures showed no bacterial growth. At 31 weeks of gestation, the wound on the right breast gradually healed with ulceration of the surrounding skin. Admitted at 38 weeks of gestation for delivery preparation, with erythematous and edematous skin on the right breast, multiple abscesses with rupture and crusting, and minimal purulent discharge; debridement was performed. At 38 +6 weeks of gestation, the patient delivered a baby girl vaginally. All ulcers healed within 4-5 months after delivery without abscess formation or purulent discharge. Postpartum breastfeeding guidance was provided in accordance with the patient's preferences. Despite inverted nipple on the affected side, successful breastfeeding was achieved through pump-assisted feeding from the affected breast and direct nursing from the unaffected breast. An eight-month follow-up confirmed sustained lactation and disease resolution.

This report detailed a case of granulomatous mastitis during pregnancy. At 25 +1 weeks of gestation, the patient presented with a 3 cm indurated mass in the upper outer quadrant of the right breast, exhibiting needle-like pain, tenderness, erythema, edema, and elevated skin temperature. Ultrasound at 26 +1 weeks of gestation revealed an 8.0 cm×2.4 cm×9.0 cm heterogeneous hypoechoic area (BI-RADS category 4B), suggestive of inflammation. Aspiration and biopsy at 27 +3 weeks of gestation confirmed granulomatous lobular mastitis. Surgical incision and drainage under general anesthesia were performed at 29 +1 weeks of gestation, and intraoperative cultures showed no bacterial growth. At 31 weeks of gestation, the wound on the right breast gradually healed with ulceration of the surrounding skin. Admitted at 38 weeks of gestation for delivery preparation, with erythematous and edematous skin on the right breast, multiple abscesses with rupture and crusting, and minimal purulent discharge; debridement was performed. At 38 +6 weeks of gestation, the patient delivered a baby girl vaginally. All ulcers healed within 4-5 months after delivery without abscess formation or purulent discharge. Postpartum breastfeeding guidance was provided in accordance with the patient's preferences. Despite inverted nipple on the affected side, successful breastfeeding was achieved through pump-assisted feeding from the affected breast and direct nursing from the unaffected breast. An eight-month follow-up confirmed sustained lactation and disease resolution.