Sporadic synchronous triple primary cancers in elderly female: Microsatellite instability high resectable colon cancer, epidermal growth factor receptor-mutated metastatic lung cancer, and neuroendocrine tumor of appendix

Colorectal cancer and lung cancer are the most common malignancies in the world. However, not all pulmonary nodules in a case of colon cancer are considered as metastasis, especially with features suggestive of limited colon disease without any nodal or liver involvement. The morphology of the pulmonary nodules is also an important consideration before subjecting the patient to another invasive procedure, as solitary pulmonary nodule with irregular margins, suggestive of another primary lesion. We describe a case of a patient with colon cancer, nonsmall cell lung cancer with single bone lesion, and neuroendocrine tumor of appendix. Initially suspected to be a case of metastatic colon cancer, the patient was later diagnosed as epidermal growth factor receptor-mutant metastatic pulmonary adenocarcinoma, with localized microsatellite instability high phenotype colon cancer.