ABSTRACT

Pyomyositis is an uncommon presentation in adults and is rarely associated with underlying primary immunodeficiency disorders. A 40-year-old male with uncontrolled diabetes presented with anterior chest wall and right thigh swelling. Contrast-enhanced computed tomography imaging revealed a superficial abscess in the chest wall and a multiloculated pus collection in the subcutaneous and intermuscular planes of the right gluteus and quadriceps, consistent with pyomyositis. Pus cultures grew methicillin-resistant Staphylococcus aureus (MRSA). Immunological workup identified chronic granulomatous disease (CGD), indicating defective nicotinamide adenine dinucleotide phosphate (NADPH) oxidase function in leukocytes. The patient was managed with surgical incision and drainage along with targeted intravenous antimicrobial therapy, followed by oral antibiotics. Following six weeks of antibiotic therapy, he was discharged in stable condition with appropriate prophylaxis to prevent recurrence. This case highlights the importance of evaluating for underlying immunodeficiency in adults presenting with severe or atypical pyomyositis.