Incidental Pulmonary Actinomycosis in a Patient With a Pancreatic Pseudocyst

Pulmonary actinomycosis is a rare manifestation of <i>Actinomyces</i> infection and is linked to aspiration, poor oral hygiene, and respiratory disease. Although timely treatment leads to favorable outcomes, pulmonary <i>Actinomyces</i> infection often presents with nonspecific symptoms and imaging findings, delaying appropriate interventions. Our 57-year-old female patient with a history of oral cancer and chronic pancreatitis presented to the emergency department with anorexia, weakness, nausea, and diarrhea. Chest and abdominal imaging raised concerns for pancreatic disease and, to our interest, an upper lobe pleural effusion. The patient was diagnosed with a pancreatic pseudocyst, and further pulmonological testing led to the additional diagnosis of pulmonary actinomycosis, ultimately confirmed by periodic acid-Schiff staining. The pulmonary infection was an incidental finding that proved to be crucial for the patient's recovery. This case report underscores the need for further research into pulmonary actinomycosis to identify potential patterns in its clinical presentation and imaging, with the aim of improving diagnostic techniques and time to appropriate interventions.