For coders working with surgeons who specialize in surgical oncology, a common coding scenario you may need to decipher is whether to code excision of a breast mass (CPT 19120) or a partial mastectomy (CPT 19301).
Before we compare some examples and determine which code would be appropriate, let’s start by looking at the description of these two codes to compare them and understand why coders sometimes struggle to choose between these codes:
CPT 19120: Excision of cyst, fibroadenoma, or other benign or malignant tumor, aberrant breast tissue, duct lesion, nipple or areolar lesion (except 19300), open, male or female, 1 or more lesions
CPT 19301: Mastectomy, partial (eg, lumpectomy, tylectomy, quadrantectomy, segmentectomy)
The term “excision” that we see in the description for CPT 19120 means “to remove.” The excision described in this code is removal of some of the breast tissue due to an area of disease such as a mass/lesion, cyst, tumor, or benign or malignant neoplasm. As we move forward with the rest of the article, we will refer to all of these abnormalities as a “mass” to keep things simple, but there are some differences in what these terms mean clinically so you can check out the definition of each by hovering over the terms in the previous sentence if you like. The term “mastectomy” that we see in CPT 19301 also means “to remove” and specifically “to remove breast tissue” (mast- or masto- means “breast” and -ectomy means “to excise”). We also see the term “partial” following the word mastectomy clarifying that, while different terms may be used to describe the procedure represented by CPT 19301, including lumpectomy, quadrantectomy, etc., all of these procedure include removal of “part” of the breast rather than removal of the entire breast. As you can see, on the surface, both codes include excision of part of the breast. So how do you distinguish between the two codes and know which CPT to pick?
For CPT 19120, the physician is excising the breast mass alone. He/she isn’t overly concerned about whether they excised the “entire mass” or if they left a small part of the mass behind. The goal is just to “roughly remove” the mass. This procedure is usually performed in cases where the surgeon suspects that the mass is non-cancerous such as a cyst or fibroadenoma. This procedure may also be performed though when the surgeon is not sure if the tissue is cancerous or non-cancerous and wants to be conservative and not remove too much of the breast tissue until he/she has the final pathology report back and knows if additional excision is warranted. CPT 19120 is reported only once per breast whether one or more lesions are removed.
On the other hand, the key you are looking for in the operative report to assign CPT 19301 for a partial mastectomy is “attention to margins.” In CPT 19301, the surgeon must ensure that he/she has “negative margins” which involves removing the mass along with a rim of normal breast tissue around the mass to make sure no diseased tissue is left behind. That rim of normal tissue removed around the mass is called a margin (meaning “the edge”) because that normal tissue removed is around the outside edge of the mass in the final specimen removed. While a partial mastectomy is not always performed to treat cancer, breast cancer is one of the most common indications for a partial mastectomy since it is particularly important with cancer to ensure that you leave no diseased tissue behind and that you have “negative margins.”
Coding tip: Not every reference to the word “margin” in an operative report for excision of a breast mass refers to ensuring that the surgeon has “negative margins” as described above. Another reference you may see to the term “margins” is when the surgeon is marking a specimen for the pathologist. He/she may say that they “oriented the specimen” and “labeled the margins” (e.g., “I then used two sutures to mark the superior, inferior, and lateral margins”). This reference to the word “margin” does not automatically make this procedure a lumpectomy because it does not refer to the intent to obtain negative margins by taking a rim of normal tissue around the breast mass to ensure no diseased tissue remains after surgery. It is not uncommon for surgeons to mark and label the “margins” (or “edges” of the specimen) for a pathologist even in a case where a breast mass was excised without particular attention to margins. The surgeon marks the edges of the specimen in this way because he/she wants the pathologist to understand how that tissue was originally positioned in the patient’s body. This information is particularly useful should the pathology come back positive for cancer because it allows the surgeon and the pathologist to speak the same language in terms of identifying which margin/edge may still have cancer present and require further excision. In this example where the surgeon is simply labeling the margins/edges for the pathologist without taking additional tissue around the mass to ensure negative margins, you would code CPT 19120 not 19301.
Let’s try out what we’ve learned with a couple of examples:
Example #1: A 64 year old patient presents with a firm mass in the upper outer quadrant of the right breast. The mass by clinical exam and mammography is highly suspicious for cancer (mammogram is a BIRADS 4). Recommendation is for excision for final diagnosis and to determine if additional treatment is warranted.
After sterile prep and drape, a curvilinear incision was made in the vicinity of the mass in the upper outer quadrant of the right breast. Dissection was carried around the mass circumferentially ensuring to take additional tissue on all sides of the mass to ensure adequate resection. Frozen pathology was positive for invasive adenocarcinoma. The pathologist also relayed that the superior margin had cancer extending to 1 mm from the inked edge so an additional cut of tissue was taken from the breast superiorly. The incision was then closed in layers.
This concludes our procedure. Patient to follow up in the office in 7-10 days for suture removal and to receive final pathology results and discuss treatment options.
Coding for Example #1: The bolded portions of the note above are clues to selecting our CPT code. We first see the surgeon “circumferentially dissecting” (or cutting all the way around) the mass and that he “is ensuring to take additional tissue on all sides to ensure adequate resection.” This statement qualifies as attention to margins because he is taking additional normal tissue all the way around the mass and being careful to ensure he has complete resection and doesn’t leave any diseased tissue behind. While some surgeons will refer to taking “margins of tissue” around the mass others will describe something that means the same thing without ever using the word margin (this is a good example of a statement that does not use the word margin but does describe attention to margins). We then see the pathologist confirms this is cancer, and he’s a bit concerned that the superior (upper) part of the specimen may still have cancer too near the margin/edge on that side so the surgeon takes additional tissue on the superior edge of the cavity he’s created in the breast. This sentence further confirms the surgeon’s “attention to margins” but even without this sentence, the first statement about taking additional tissue to ensure adequate resection would support attention to margins. Based on these details, this example would be coded with CPT 19301. I would also add modifier RT since this procedure occurs on the right breast, and CPT 19301 allows modifier 50 for a bilateral procedure on both sides per the Medicare Physician Fee Schedule (MPFS). When a code allows modifier 50, the laterality modifiers RT or LT would apply to that same code when the procedure described by the code is performed only on one side.
Example #2: A 27-year-old patient presents with a lump in the left lower quadrant of the left breast. Clinical presentation and ultrasound findings are consistent with a benign fibroadenoma. Patient was offered options of surgical excision vs. close interval monitoring with repeat ultrasounds and mammography. Patient has elected to have the area removed.
After sterile prep and drape, the area of concern in the left lower quadrant of the left breast was identified, and we made a circumferential incision around the palpable mass. The mass was excised and placed in formalin for transport to pathology. We carefully inspected our cavity and ensured hemostasis. The incision was closed in layers with sutures.
The patient will follow up in 7-10 days for a wound check and pathology results.
Coding for Example #2: The bold portions of the note above are clues to selecting our CPT code. This case starts similar to example #1 with a circumferential incision (an incision all the way around) the mass. From there though, we see that the surgeon excises the mass alone and sends it off for pathology which is typical anytime tissue is removed from the body. We see no excision of any additional tissue around the mass and no mention of the intent to ensure that no diseased tissue is left behind (no “attention to margins”). The goal is simply to remove the mass which is expected to be a benign area. This documentation supports CPT 19120. I would also add modifier LT since the procedure occurs on the left breast, and this CPT also permits modifiers 50/LT/RT per the MPFS.
