Question: One of our patients had known invasive ductal carcinoma of the breast and had a mastectomy. The axillary contents were removed at the time of the mastectomy, and the breast tissue and lymph nodes are all on the same pathology report. The report states the provider examined a total of seven nodes, and three of them were tumor cells. Even though the pathology report doesn’t state specifically what type of tumor cells are shown in the lymph nodes, would that be coded to lymph node metastasis? AAPC Forum Participant Answer: As the lymph nodes were collected at the time of the mastectomy, they should be considered as metastatic. Depending on whether the patient is in active treatment for both conditions, you would code the primary and metastatic sites in this situation by choosing the applicable code from C50.- (Malignant neoplasm of breast) and a code from C77.- (Secondary and unspecified malignant neoplasm of lymph nodes). Caveat: This would be a situation where you should query your provider and make sure the coding for this encounter is accurate.