Internal Medicine Coding Alert

Question: If the internist sees a patient for metastasis to the lung, and the cancer originated in the breast, how should I code this?


Michigan Subscriber

Answer: For your primary diagnosis code, you should list the lung metastasis code 197.0 (Secondary malignant neoplasm of respiratory and digestive systems; lung), even though the metastasis is the secondary condition.

Why: When the internist treats a patient because of a primary neoplasm with metastasis and directs the treatment toward the secondary site only, you should note the secondary neoplasm as the principal diagnosis.

To assign the correct secondary code, you'll need to know whether the physician has done three things: previously excised or eradicated the primary malignancy,
stopped treating the original neoplasm's site, andfound no evidence of existing primary malignancy.

If the physician has done all three, you should assign history-of-cancer code V10.3 (Personal history of malignant neoplasm; breast) as the secondary code. But if not, you may list 174.9 (Malignant neoplasm of female breast; breast [female], unspecified).