Bacterial Synergism in Breast Necrotizing Fasciitis: A Case Report on Diagnostic Dilemmas, Therapeutic Challenges, and Reconstructive Management.

Necrotizing fasciitis (NF) is a rapidly progressive, life-threatening soft tissue infection that primarily involves the fascia and subcutaneous tissues. While it typically affects the extremities, perineum, or trunk, NF of the breast remains an exceptionally rare and underdiagnosed entity, often leading to delayed intervention and high morbidity. We report the case of a 57-year-old woman with poorly controlled Type 2 diabetes who presented to the emergency department with diabetic ketoacidosis and erythema of the left breast. Initial arterial blood gas analysis revealed profound metabolic acidosis (pH 6.89, PaCO 12.8 mmHg, bicarbonate 2.5 mmol/L, and base excess -31.5 mmol/L). Despite initial antibiotic therapy, the breast symptoms worsened, raising concern for inflammatory breast cancer. Imaging revealed subcutaneous emphysema and extensive soft tissue inflammation. A diagnosis of NF was confirmed, prompting emergency surgical intervention. A left mastectomy was performed, with resection of necrotic fascia and pectoralis major. Microbiological cultures identified a polymicrobial infection with , , and . The patient received targeted antibiotic therapy and supportive care, including pain management and fluid-electrolyte balance. Reconstruction was initiated 8 months later with contralateral breast reduction and fat grafting. Breast NF poses significant diagnostic challenges due to the organ's unique vascular anatomy and the rarity of the condition. Delays in diagnosis can be fatal. This case underscores the importance of clinical vigilance, prompt imaging, and early surgical debridement. The synergistic effect of polymicrobial infections was evident in the rapid progression. Reconstruction remains an essential component of care, with satisfactory outcomes achievable through fat grafting and symmetry procedures. Breast NF requires rapid diagnosis and aggressive multidisciplinary management. This case illustrates the need for increased awareness to reduce diagnostic delays and improve survival and reconstructive outcomes.