Code selection for breast excision procedures presents many challenges, not the least of which is distinguishing between a lesion excision as described by 19120 Excision of cyst, fibro-adenoma, or other benign or malignant tumor, aberrant breast tissue, duct lesion, nipple or areolar lesion (except 19300), open, male or female, one or more lesions (APC 0028, status indicator T) and a partial mastectomy, identified with 19301 Mastectomy, partial (for example, lumpectomy, tylectomy, quadrantectomy, segmentectomy) (APC 0028, status indicator T).

Neither CPT instructions nor national payor rules define precisely when a lesion excision "crosses the line" to become a partial mastectomy. In fact, the volume of tissue removed is not the issue. Whether the surgeon removes 50% or 20% of the breast tissue, the procedure may qualify as a partial mastectomy. Rather, you must consider the surgeon's intent when performing the excision and, specifically, the extent of margin he removes along with the target tissue.

• 19301. If the surgeon removes a breast lesion along with a margin of healthy tissue, you may choose the partial mastectomy code 19301. CPT doesn't specify the margin width necessary to define a partial mastectomy. In the surgeon's best clinical judgment, however, the margins must be "adequate" to remove all possible malignant tissue surrounding the excised mass. In the best-case scenario, the operative note will document, "Allowed minimum margins sufficient to remove all suspected malignancy," or a similar statement.
• 19120. If the surgeon removes only the tumor, with no or very little margin, you should select 19120 (lesion excision) over the partial mastectomy code (19301). Be cautious if you see "lumpectomy," "tylectomy," "quadrantectomy," or "segmentectomy" documented in the operative note. These terms, although a part of the descriptor for 19301, are applied so subjectively that they could, in fact, describe either 19301 or 19120.
• Modifier 58. On occasion, a surgeon may remove a lesion with minimal margins (19120) and, upon subsequent review of the pathology report, return the patient to the operating suite for further excision to eliminate remaining malignancy. In such a case, the re-excision likely will qualify as a partial mastectomy (19301). When billing physician services, you'd append modifier 58 to such a staged or related procedure during the post-operative period. Under CMS rules you should not, however, append modifier 58 to ASC facility fee claims.
• 38500 and 38525. Along with partial mastectomy, the surgeon may perform sentinel lymph node biopsy and/or complete excision of the axillary lymph nodes. For lymph node biopsy, you may report either 38500 Biopsy or excision of lymph node(s); open, superficial (APC 0113, status indicator T) or 38525 Biopsy or excision of lymph node(s); open, deep axillary node(s) (APC 0113, status indicator T), based on the surgeon's documentation. To support "deep" code 38525, the surgical note should provide evidence that that the lymph node dissection was below the fascia, or under a muscle mass or bone.

Deep excision or biopsy (38525) is inclusive of superficial excision or biopsy (38500) at the same location, but either 38500 or 38525 may be reported in addition to 19301.

• 19301 and 38745. Complete axillary lymph node dissection also may accompany a partial mastectomy. In other words, along with excision of breast tissue, the surgeon also may remove the lymph nodes in the axilla (between the pectoralis major and pectoralis minor) through a separate incision at the same time.
• 19302. When performed independently of one another (for instance, when performed at different sessions or different breasts), you may report a partial mastectomy and axillary lymphadenectomy separately, using 19301 and 38745 Axillary lymphadenectomy; complete (APC 0114, status indicator T), respectively. If the partial mastectomy and axillary lymphadenectomy occur at the same breast during the same session, however, you should cite the "combined" code 19302 Mastectomy, partial (for example, lumpectomy, tylectomy, quadrantectomy, segmentectomy); with axillary lymphadenectomy) (APC 0030, status indicator T), rather than claiming 19301 and 38745 separately.

Don't separately report sentinel node biopsy (38500, 38525) and a planned lymphadenectomy (either alone, 38745; or with partial mastectomy, 19302) in the same region during the same operative session. Instead, include the sentinel node biopsy in the more extensive, planned, same-location lymphadenectomy.

• 38525 and 19302. If, however, the surgeon performs a sentinel node biopsy before an unplanned partial mastectomy (either with or without lymphadenectomy) — and the subsequent excisions are a result of biopsy findings — you may report the sentinel node biopsy separately. National Correct Coding Initiative guidelines specify that "Sentinel lymph node biopsy is separately reported when performed prior to a localized excision of breast or a mastectomy with or without lymphadenectomy." Let's say the surgeon biopsies several deep sentinel nodes. Pathology indicates that malignancy has spread, and the surgeon returns the patient to the operating suite several days later for partial mastectomy with axillary lymphadenectomy. Because the biopsy led to the decision to perform the mastectomy, you may report both 38525 and 19302.