Accessory breast

This code describes the presence of supernumerary breast tissue, which is additional breast tissue found outside the normal anatomical location of the breasts. This can range from a small patch of glandular tissue to a fully formed extra nipple and areola, with or without underlying glandular tissue. It is a congenital anomaly resulting from incomplete regression of the mammary ridge during embryonic development.

Use this code when documentation clearly indicates the presence of an accessory breast, polymastia, or supernumerary breast tissue. This includes findings during physical examination, imaging studies, or surgical removal of such tissue. The diagnosis should be explicitly stated or clearly inferable from the clinical findings.

• Do not confuse with gynecomastia (enlargement of male breast tissue) or other benign breast conditions.
• Ensure the documentation specifies "accessory breast" or "supernumerary breast" rather than just a "mass" to support this specific code.
• If the accessory breast is symptomatic (e.g., pain, discharge, malignancy), code the symptom or malignancy first, followed by this code as a secondary diagnosis.