An invasive and diffuse cranial actinomycosis with a dura-based mass mimicking a brain tumor: illustrative case

Actinomycosis is a chronic suppurative infection caused by non-spore-forming, anaerobic, and filamentous gram-positive bacteria. Primary central nervous system involvement is rare, with no specific clinical features, causing a clinical diagnostic dilemma. Imaging can help in localizing and characterizing the lesion; however, a definitive diagnosis relies on culture and/or histopathology.