A case of a surgically treated primary quartet cancer is reported, along with a review of the Japanese literature. A 68-year-old woman, curatively operated for a right breast cancer 6 years previously, was then diagnosed as having a left renal cell carcinoma, a thyroid cancer, and a sigmoid colon cancer as a result of a subsequent screening examination within one year. These synchronous, triple cancers were resected in a curative operation for each. Histopathologically, each neoplasm was proven to be a primary cancer lesion, and two different types (papillary and trabecular) were found in the thyroid gland.