Malignant carcinoid tumor of the duodenum

This code represents a neuroendocrine tumor originating in the duodenum, characterized by its malignant nature. These tumors arise from enterochromaffin cells and can produce various hormones, though they are often non-functional. Malignant carcinoid tumors of the duodenum have the potential to metastasize.

Use this code when documentation confirms a primary malignant carcinoid tumor located specifically in the duodenum. This diagnosis is typically established through biopsy and histopathological examination. Supporting documentation should include pathology reports and physician notes detailing the tumor's location and malignant characteristics.

• Ensure the pathology report explicitly states "malignant" and "carcinoid tumor" of the duodenum.
• Do not confuse with benign carcinoid tumors or neuroendocrine tumors of other gastrointestinal sites.
• Sequence this code as the primary diagnosis when it is the reason for the encounter, followed by codes for any associated symptoms or metastatic sites.