Primary Chest Wall Abscess Mimicking a Breast Tumor That Occurred after Blunt Chest Trauma: A Case Report

Primary chest wall abscess occurring after blunt chest trauma is rare. We present the case of a 50-year-old woman who presented with a swelling in her left breast. The patient had experienced blunt chest trauma 2 months back. Needle aspiration revealed pus formation in the patient’s chest. Computed tomography revealed a mass in the lower region of the left mammary gland, with thickening of the parietal pleura and skin and fracture of the fifth rib under the abscess. Following antibiotic administration and irrigation of the affected region, surgical debridement was performed. During surgery, we found that the pectoralis major muscle at the level of the fifth rib was markedly damaged, although the necrotic tissue did not contact the mammary gland. We diagnosed the lesion as a chest wall abscess that occurred in response to blunt chest trauma. Her postoperative course was uneventful. There has been no recurrence for six months after surgery. 1. Introduction Chest wall infections can be categorized as primary and secondary infections, with the former arising spontaneously (primary chest wall abscess) and the latter occurring in response to preexisting disease states or irritation caused by other procedures (secondary chest wall abscess) [1]. We report the case of a 50-year-old woman who developed a primary chest wall abscess with breast tumor—like features that developed after rib fracture caused by blunt chest trauma. 2. Case Report A 50-year-old Japanese female presented at our institute with a swelling in her left breast (Figure 1). She had received a blow to her anterior chest 2 months back, but she did not seek immediate medical consultation at that time. The patient reported no history of major medical diseases such as diabetes mellitus, cardiovascular disease, or renal disease, and she did not smoke, consume alcohol, or take any medications. Physical examination revealed a firm and tender mass in the lower region of the left breast. No lymph nodes were palpable in the bilateral axillary fossa and cervix. Ultrasound revealed a hypoechoic mass with a hyperechoic boundary toward the subcutaneous tissue (Figure 2). Laboratory evaluation revealed a white blood cell (WBC) count of 20,000/μL and a C-reactive protein (CRP) level of 12.3？mg/dL. Serum levels of carcinoembryonic antigen, CA 15-3, and NCC-ST-439 were all within normal limits. Computed tomography (CT) revealed a large mass measuring 10？cm × 10？cm in the lower region of the left breast, with pleural and skin thickening and fracture of the fifth rib under the mass (Figure 3(a)). Contrast-enhanced