Secondary malignant neoplasm of small intestine

This code signifies the presence of a malignant tumor in the small intestine that originated from a primary cancer elsewhere in the body and has metastasized to this location. It indicates that the small intestine is a site of secondary cancer, not the initial origin of the malignancy.

Apply this code when documentation clearly states metastatic cancer to the small intestine. This typically occurs in patients with a known primary malignancy, such as colorectal, lung, or breast cancer, where imaging or biopsy confirms small intestinal involvement.

• Always sequence the primary malignancy code first, followed by this code for the secondary site.
• Do not use this code if the small intestine is the primary site of the malignancy; refer to codes in the C17 series for primary small intestinal cancers.
• Ensure the medical record explicitly states "metastatic to small intestine" or "secondary malignant neoplasm of small intestine."