A Rare Case of Empyema Necessitans Due to Streptococcus Anginosus with Necrotizing Fasciitis and Retroperitoneal Abscesses

Background: Necrotizing fasciitis (NF) is a rapidly progressive soft-tissue infection associated with high mortality even when recognized early. Empyema necessitans (EN) is an uncommon complication of pleural empyema in which purulent material extends beyond the thoracic cavity into surrounding soft tissues. Although classically linked to Mycobacterium tuberculosis and Actinomyces, EN due to Streptococcus anginosus is distinctly rare. In exceptional cases, extra thoracic spread of empyema can track along fascial planes and evolve into NF. Case report: A 36-year-old previously healthy woman, recently treated for bilateral empyema, re-presented in severe respiratory distress and septic shock. She was found to have a foul-smelling open thigh wound, widespread soft-tissue involvement, and laboratory evidence of severe infection. Computed tomography (CT) imaging demonstrated bilateral multiloculated empyema with chest-wall extension consistent with EN, NF of the right thigh, multiple large retroperitoneal abscesses, and emphysematous cystitis (EC). She required intubation, vasopressor support, broad-spectrum antibiotics, and multiple surgical debridements. Pleural cultures grew S. anginosus. Retroperitoneal abscesses were managed conservatively, and multidisciplinary care led to steady clinical improvement. After approximately 5 weeks, her empyema had resolved, and her thigh wounds healed adequately, allowing discharge on oral antibiotics. Conclusion: This case illustrates an exceptionally rare progression of S. anginosus empyema to EN with concurrent NF and widespread retroperitoneal involvement. Early recognition of atypical dissemination, aggressive surgical management, and coordinated multidisciplinary care are essential for survival in such complex presentations.