Quadruple primary malignancy patient with survival time more than 20 years.

Multiple primary carcinoma (MPC) is defined as two or more carcinomas without subordinate relationship detected in the same or other organs of an individual patient. The diagnosis of MPC must comply with the following standards: each of the tumors must present a definite picture of malignancy, each tumor must be histologically distinct, and the probability of one being a metastasis of the other must be excluded. MPC often occurs in the digestive system, but its pathogenesis remains unclear involving genetic susceptibility, tumor immunity and iatrogenic factors, including radiotherapy and chemotherapy. Most MPC patients are double primary malignancy; the occurrence of quadruple primary malignancy is below 0.1%. Here we present a rare case of quadruple primary malignancy involving the small intestine, descending colon, renal pelvis and pancreas. Due to its rarity, the relevant literature is also reviewed. In general, the incidence of MPC is rising, so prevention, early diagnosis and treatment will become necessary and important. Therefore, further research should focus on the etiology and mechanism of MPC.