Secondary malignant neoplasm of breast

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

Apply this code when documentation clearly states a metastatic malignancy to the breast, with the primary site identified as originating from another organ. This is commonly seen in cases where a primary lung, ovarian, or gastrointestinal cancer has spread to the breast.

• Always sequence the primary malignant neoplasm first, followed by this code for the secondary site.
• Do not use this code for primary breast cancer; use codes from the C50.- category for primary breast malignancies.
• Ensure the medical record explicitly states "metastatic to breast" or "secondary malignant neoplasm of breast" to support its use.