Diagnosis Coding Help

Question:

I need some guidance. A general surgeon did a left mastectomy four months ago for a patient who had breast cancer. My plastic surgeon did a breast reconstruction yesterday. What diagnosis code do I use?

Answer:

You would report 3 codes, the encounter for breast reconstruction following mastectomy Z42.1, Personal history of breast cancer Z85.3 and Z90.12 for the acquired absence of the left breast.