There are many different types of gallbladder diseases, mainly resulting from inflammation. The long-term presence of an insult to the gallbladder leads to chronic inflammation, which is a nidus for complications such as Mirizzi syndrome and gallbladder cancer, both of which can become mimics of one another. Preoperative diagnosis of either gallbladder cancer or Mirizzi syndrome is often difficult, leading to late diagnosis and complicating the patient's treatment course. We report a case of a 65-year-old male who presented with abdominal pain and significant weight loss, with no physical evidence of jaundice and normal liver function. This was initially diagnosed as acute cholecystitis and Mirizzi syndrome before being diagnosed as gallbladder adenocarcinoma on final histology.