Although the appearance of abnormal lipoproteins in liver diseases is well known, the precise analyses of abnormal lipoproteins remain elusive. Here, we report a 71-year-old woman with type 2 diabetes whose serum cholesterol levels were elevated to 560 mg/dL over a 4-month period. High-performance liquid chromatography demonstrated the presence of lipoprotein-X and lipoprotein-Y and sigmoid colon cancer and multiple liver metastases were found by colonoscopy and computed tomography. Remission of the primary colon cancer and liver lesions was achieved by chemotherapy with oxaliplatin and fluorouracil and her serum cholesterol went back to basal levels associated with the disappearance of abnormal lipoproteins.