A case of metachronous ascending colon cancer and synchronous primary rectal and duodenal cancer in a patient with Lynch syndrome

Abstract

Multiple primary malignant tumours (MPMTs) are defined as the simultaneous or sequential occurrence of two or more primary malignant tumours in a single patient, which may originate from the same organ, paired organs, different parts of the same system, or different organs. Synchronous MPMTs develop within 6 months of the primary tumour, while metachronous ones occur more than 6 months later. The available sources have no information on metachronous or synchronous colorectal and duodenal cancer.