A Single-Center Study of Patients With Synchronous Primary Malignancy: A Case Series.

Multiple primary malignant tumors (MPMT) can be defined as more than two different tumors synchronously or metachronously forming in the same organ or different organs. The incidence of MPMTs varies dramatically between antemortem and postmortem examinations, becoming a serious medical issue. Evidence shows that the overall incidence of MPMTs is between 2.