Part B Insider (Multispecialty) Coding Alert

Question: I’ve heard that the distinguishing difference between 19303 and 19304 is whether the surgeon removes the pectoral fascia — is that correct?

Answer: No, removing the pectoral fascia is not the key factor that distinguishes 19303 (Mastectomy, simple, complete) from 19304 (Mastectomy, subcutaneous). 

Code 19304 describes a subcutaneous mastectomy, and the key feature is that the procedure is skin-sparing. The surgeon removes breast tissue through an incision under the breast, leaving the skin, areola, and nipple. Surgeons perform this procedure only if the skin is not affected by malignancy, often for conditions such as severe fibrocystic disease. Although this procedure involves the surgeon leaving the pectoral fascia intact, that is not the key feature of the procedure.

On the other hand, 19303 describes removal of entire breast, nipples, and skin. Although the surgeon leaves the pectoralis major and minor muscles and axillary nodes in place during this procedure, he may or may not remove the pectoral fascia, which is a lamina covering the pectoral major muscle.