My mom had ct scan showed calcification focus within gallbladder the doctor said its not gall stone. are they thinking this is cancer? has to haveu/s

Making sure its not : The calcification, if not a mobile stone, may represent mural calcification (gallbladder wall calcification), porcelain gallbladder, rare condition believed to be caused by chronic cholecystitis (exact cause is unclear). In these patients a prophylactic cholecystectomy has been advocated due to association with gallbladder cancer, although the association with gb cancer appears to be weak(~1-5%).