The gallbladder wall is thickened by oedema as well as by fibromuscular hyperplasia, as seen by the pale tan colour. Oedema is seen in acute cholecystitis, while fibromuscular hyperplasia is seen in chronic cholecystitis. Focal areas of mucosal congestion are present at the distal luminal aspect, with a suggestion of mucosal erosion, these features also indicate the presence of acute cholecystitis.