Case report: Quadruple primary malignant neoplasms including esophageal, ureteral, and lung in an elderly male.

Multiple primary malignant neoplasms (MPMNs) are defined as multiple tumors with different pathogenic origins. MPMNs are rare, but the morbidity rate is on the rise. With the development of anti-tumor treatments, such as targeted therapy and immunotherapy, the overall survival of cancer patients has been significantly prolonged, leading to an increased number of patients with MPMNs. A crucial aspect of MPMNs management is deciding how to schedule further treatments according to individual tumor risk. This process involves a multidisciplinary physician team to ensure favorable outcomes. Herein we report a 60-year-old male who developed four different malignancies, including esophageal squamous cell carcinoma, upper urinary tract urothelial carcinoma, mediastinal small cell lung cancer, and left lung squamous cell carcinoma over 20 years and received appropriate treatment of each cancer with long survival.