Edema of the gallbladder may pose a diagnostic challenge because it also occurs in patients without an indication for cholecystectomy.We evaluated all consecutive patients with gallstone disease who presented for cholecystectomy at the Department of Surgery of Kansai Medical University from January 2006 to April 2019. Using the prospectively collected database in our department, we obtained information on patients whose final diagnoses were gallbladder edema. We identified 12 patients with gallbladder edema who were misdiagnosed with acute cholecystitis among 2661 patients and who presented for cholecystectomy for benign gallbladder diseases. The outcome of these patients was assessed to prevent unnecessary cholecystectomy.In all 12 patients, computed tomography and ultrasonographic imaging showed gallbladder wall thickening. Acute cholecystitis was suspected, and emergent cholecystectomy was performed for the first 5 patients. Of these 5 patients, 2 patients died of liver failure postoperatively. Based on the misdiagnosis in the first 5 patients, the latter 7 patients did not undergo cholecystectomy; instead, they were treated specifically for their systemic disease. To date, no cholecystitis has occurred in these 7 patients. In all misdiagnosed cases in the present report, mesh-like wall thickening was a distinctive feature of gallbladder edema on ultrasonography. We consider this feature important for distinguishing simple gallbladder edema from cholecystitis.Careful evaluation of clinical symptoms and imaging findings, especially mesh-like wall thickening on ultrasonography, is necessary in this setting to prevent misdiagnosis and unnecessary cholecystectomy.