Primary coexisting adenocarcinoma of the colon and neuroendocrine tumor of the duodenum: A case report and review of the literature

BACKGROUND Neuroendocrine tumors(NETs)arise from the body’s diffuse endocrine system.Coexisting primary adenocarcinoma of the colon and NETs of the duodenum(D-NETs)is a rare occurrence in clinical practice.The classification and treatment criteria for D-NETs combined with a second primary cancer have not yet been determined.CASE SUMMARY We report the details of a case involving female patient with coexisting primary adenocarcinoma of the colon and a D-NET diagnosed by imaging and surgical specimens.The tumors were treated by surgery and four courses of chemothe-rapy.The patient achieved a favorable clinical prognosis.CONCLUSION Coexisting primary adenocarcinoma of the colon and D-NET were diagnosed by imaging,laboratory indicators,and surgical specimens.Surgical resection com-bined with chemotherapy was a safe,clinically effective,and cost-effective treat-ment.