Synchronous double primary gastric and endometrial cancer: a case report and literature review.

Multiple primary malignant neoplasms (MPMN) are two or more malignancies in an individual without any relationship between the tumors. In recent years, increasing number of cases were reported. However, Synchronous double primary gastric and endometrial cancer are relatively rare to be reported. Here we present a rare case of synchronous double cancer involving the stomach and endometrium, which is resected simultaneously and received six times chemo. After reviewing lots of literatures at home and abroad, we discuss the risk factors, the diagnostic criteria, the treatment modalities and the prognosis of these rare MPMN. Although a number of risk factors have been proposed in a mass of literatures, but the mechanism of MPMN is still unclear. We didn't discover a detailed explanation for the mechanism of MPMN from our patient. Therefore, further research should focus on the etiology and mechanism of MPMN.