Introduction: Portal vein aneurysms (PVA) and intrahepatic portosystemic venous shunts are rarely diagnosed clinically. Patient Concerns: A 75-year-old female was admitted to our hospital for evaluation of significant weight loss, diabetes, and an irregularly shaped cystic lesion in the left lateral lobe of the liver. Diagnosis: The patient was diagnosed with a portal vein aneurysm combined with an intrahepatic portosystemic venous shunt using multiple imaging techniques. Interventions: The patient had no relevant clinical symptoms of PVA with concurrent intrahepatic portosystemic venous shunt; hence, no interventions were performed. Ultrasonography was suggested to be performed every 3 months. Outcomes: The patient did not visit the hospital after discharge; however, 4 telephonic follow-up evaluations showed that the patient was well. Lessons: Multimodal imaging techniques should be used to evaluate the source of blood flow, presence or absence of shunts, and the course, number, and location of the shunts to prevent misdiagnosis of this disease.