Malignant neoplasm of abdomen

This code signifies the presence of a primary cancerous tumor located within the abdominal cavity, but where the specific organ of origin cannot be determined or is not specified in the medical record. It indicates a malignancy originating in the abdomen rather than a metastatic spread from another site.

Use this code when documentation clearly states a primary malignant neoplasm of the abdomen without further specification of the affected organ (e.g., "abdominal cancer, site unspecified"). It is appropriate when the physician has diagnosed a primary abdominal malignancy but the exact anatomical location within the abdomen is unknown or not documented.

• Do not use this code if a more specific primary site within the abdomen (e.g., stomach, colon, liver) is documented.
• Ensure documentation specifies "primary" to differentiate from metastatic disease to the abdomen.
• If the primary site is known but the malignancy has spread to the abdomen, code the primary site and then use a secondary malignancy code for the abdominal involvement.