Malignant neoplasm of colon, unspecified

This code signifies the presence of a cancerous tumor originating in the colon, where the specific anatomical subsite within the colon (e.g., ascending, transverse, descending, sigmoid) has not been documented or cannot be determined. It indicates a primary malignancy of the large intestine.

This code is appropriate when the medical record clearly states a diagnosis of colon cancer but lacks further specification regarding the precise location within the colon. It should be used when documentation indicates "colon cancer, NOS" or "malignant neoplasm of colon, site unspecified."

• Avoid using this code if any specific colon subsite (e.g., C18.0 for cecum, C18.2 for transverse colon) is documented.
• Prioritize more specific anatomical codes when available, as this code represents an unspecified site.
• Ensure the documentation confirms a primary malignancy and not a metastatic site to the colon.