Malignant neoplasm of duodenum

This code identifies a primary cancerous tumor originating in the duodenum, the first section of the small intestine. It signifies a malignant growth that has developed from the duodenal tissue itself, rather than a metastasis from another site.

Apply this code when documentation confirms a primary malignant neoplasm located specifically within the duodenum. This diagnosis is typically supported by pathology reports from biopsies or surgical resections, imaging studies, and physician notes detailing the tumor's origin.

• Ensure the documentation specifies "primary" malignancy of the duodenum; if metastatic, a secondary site code is appropriate.
• Do not confuse with malignant neoplasms of other small intestine segments (jejunum, ileum) or unspecified small intestine.
• Sequence this code as the primary diagnosis when it is the reason for the encounter or treatment.