Case Report: Staged topical herbal therapy for giant plasma cell mastitis in pregnancy with 3-year follow-up.

Background: Plasma cell mastitis (PCM) is a benign immune-mediated inflammatory breast disease predominantly affecting non-lactating women. In pregnant patients, conventional treatments carry significant maternal-fetal safety risks, creating an unmet need for safe, non-invasive therapeutic strategies. Case presentation: A 30-year-old primigravida at 16 weeks of gestation presented with a giant (>15 cm), antibiotic-refractory left breast PCM. She declined systemic corticosteroids and surgical intervention due to fetal safety concerns. An individualized three-stage topical herbal residue dressing regimen was implemented, with dynamic prescription adjustments from mass resolution to wound healing to postpartum consolidation. Oral herbal medicine was added postpartum when fetal safety was no longer a constraint. Results: Clinical cure was achieved, defined as complete resolution of the palpable mass and ulcer healing. A notable discordance between clinical and imaging recovery was observed, with residual hypoechoic areas requiring over 1 year to achieve near-complete resolution. The patient remained recurrence-free throughout a 3-year follow-up period, including a 2-year treatment-free phase. A healthy full-term infant was delivered vaginally with normal neonatal development. Conclusion: This case suggests that staged topical herbal therapy may represent a potential option for managing gestational PCM in carefully selected patients. These findings may serve as a reference for clinicians managing similar cases but require confirmation through larger controlled studies before definitive clinical recommendations can be made.