Actinomycosis of the gallbladder.

Actinomycosis of the gallbladder is rare, and the pathogenesis of the infection is poorly understood. The authors report the case of a 77-year-old man admitted to hospital because of abdominal pain. Clinical and laboratory findings suggested the diagnosis of cholecystitis and cholelithiasis. At cholecystectomy the gallbladder was inflamed and contained many calculi. Gram staining of material from the mucosa of the gallbladder demonstrated gram-positive pleomorphic filaments, and Actinomyces israelii grew in pure culture, thus confirming the diagnosis of actinomycosis of the gallbladder. The pathogenesis of the condition is also discussed.