Abstract
Actinomycosis is a chronic granulomatous disease that can affect various parts of the body, including the head and neck, lungs, abdominal and pelvic cavities, and wounds. It is caused by different actinomycetes like Actinomyces sherdii, Actinomyces glasii, Actinomyces cariosa, Actinomyces zurichensis, and Actinomyces europaea. Reported infections caused by actinomycetes include pulmonary actinomycosis, pelvic and abdominal infections, bone or artificial joint infections, endocarditis, complicated urinary tract infections, and soft tissue abscesses. The combination of pulmonary actinomycosis with gastric cancer is exceptionally rare in clinical practice, and the presence of actinomycetal infection alongside tumors in elderly patients poses significant challenges in treatment. This article presents the diagnosis and treatment process of an elderly patient with pulmonary actinomycosis and gastric adenocarcinoma.