Mesothelioma is a difficult-to-detect neoplasm that rarely develops in the peritoneum. In patients with unexplained ascites, pleural fluid analysis and ultrasonography is often the first step to achieving a diagnosis. This case report shares a unique presentation in which a patient who presented with unexplained ascites, was initially thought to have cirrhosis but was later found to have malignant peritoneal mesothelioma after cross-sectional imaging and tissue acquisition. This case illustrates the importance of a high clinical index of suspicion for mesothelioma given its variety of clinical presentations, as well as the utility of early cross-sectional imaging in such cases.