Gallbladder adenosquamous carcinoma with extensive necrosis mimicking gangrenous cholecystitis and liver abscess.

We report a case of gallbladder adenosquamous carcinoma with characteristic imaging findings. A 78-year-old man was suspected of having gangrenous cholecystitis and liver abscess based on abdominal ultrasonography performed at another hospital. Contrast-enhanced computed tomography revealed a 10-cm hepatic mass contiguous with the gallbladder, with marked internal necrosis and persistent peripheral enhancement. These imaging findings suggested gallbladder adenosquamous or squamous cell carcinoma with hepatic invasion, and needle biopsy revealed both adenocarcinoma and squamous cell carcinoma components, supporting the diagnosis. This case highlights the importance of recognizing marked internal necrosis and aggressive infiltrative growth on imaging in gallbladder adenosquamous carcinoma presenting with imaging features mimicking gangrenous cholecystitis and liver abscess.