A 72-year-old male patient was hospitalized with diffused abdominal pain with worsening renal insufficiency, intermittent vomiting, and a spiking fever. Initial CT scan and sonography showed a dilated gallbladder with a polyp, but no calculi. A gallium scan with SPECT/CT revealed intense gallbladder uptake with a cold central area. Acute gangrenous cholecystitis was suspected as the likely diagnosis and cause of his discomfort and fever. Subsequent cholecystectomy confirmed the diagnosis.