General Surgery Coding Alert

Question: Following a right mastectomy for invasive ductal carcinoma, the patient had a small local recurrence in the chest wall incision six months later. The surgeon performed a second procedure at that time, marking an ellipse over the area of the lesion measuring 3 x 4 cm and excising tissue to the intramuscular layer. Should we use a mastectomy code or a chest wall code?

Missouri Subscriber

Answer: You should not use a mastectomy code such as 19301 (Mastectomy, partial (eg, lumpectomy, tylectomy, quadrantectomy, segmentectomy)), because the procedure does not remove a portion of the breast. Nor should you use a chest wall code such as 21601 (Excision of chest wall tumor including rib(s)), because there is no documented bone involvement.

The best code for the case you describe is 21556 (Excision, tumor, soft tissue of neck or anterior thorax, subfascial (eg, intramuscular); less than 5 cm). The surgeon documents the anatomic site and the depth of the excision, which indicates that the soft tissue code is appropriate.

You should not use an integumentary code such as 11604 (Excision, malignant lesion including margins, trunk, arms, or legs; excised diameter 3.1 to 4.0 cm) because CPT^® defines codes in this section as “full-thickness (through the dermis),” which does not account for the depth of the documented excision.