Identify Margins, Measurements, and Malignancy for WLE Coding
Also, learn how to navigate closures and modifiers for malignant lesion excision. A wide local excision (WLE) is a surgical procedure performed with a scalpel to remove abnormal tissue along with a margin of surrounding healthy tissue. To assign the correct CPT® code for a melanoma WLE (distinct from shaving or destruction), three variables must be evaluated: pathologic classification, anatomical location, and excised diameter. Let Revenue Cycle Insider guide your coding approach step by step with this handy guide. Review This Example Situation Scenario: A patient presents with a 2 cm melanoma on their neck. The physician injects local anesthetic, makes a full-thickness incision through the dermis, and removes the lesion with a 0.5 cm margin of healthy tissue on all sides. The physician then closes the wound in a single-layer, simple closure. How should you code this surgical encounter? Step 1: Identify the Pre-Excision Measurements Timing: The physician should measure the lesion prior to excision and record the measurements on the operative report. Don’t base code selection on the length of the incision line, the final surgical defect, or the postoperative pathology report. Excised tissue shrinks after being removed and placed in formalin, which can lead to undercoding. Converting units: Malignant lesion excision codes are categorized in centimeters (cm). If the physician documents measurements in millimeters (mm), convert the units prior to coding by multiplying the mm measurement by 0.1 to find the measurement in cm. For example, a 15 mm lesion is a 1.5 cm lesion. Step 2: Select the Anatomic Location CPT® divides full-thickness malignant excisions into three anatomical categories: Anatomical Sites Included CPT® Code Series Trunk, arms, or legs (including wrists and ankles) 11600-11606 (Excision, malignant lesion including margins, trunk, arms, or legs …) Scalp, neck, hands, feet, and genitalia 11620-11626 (Excision, malignant lesion including margins, scalp, neck, hands, feet, genitalia …) Face, ears, eyelids (skin only), nose, and lips 11640-11646 (Excision, malignant lesion including margins, face, ears, eyelids, nose, lips …) Coding tip: Assign 19120 (Excision of cyst, fibroadenoma, or other benign or malignant tumor, aberrant breast tissue …) for breast tissue lesions (not breast skin). Pathology hold: CPT® separates lesion excision into benign and malignant categories. Malignant codes are only used when pathology has confirmed malignancy. Hold the claim until this information is confirmed. A prior biopsy confirming malignancy satisfies this requirement. Melanoma is malignant by its nature; there is no benign melanoma. Coding tip: If the provider performed Mohs micrographic surgery (MMS) on the lesion during the same encounter, report Mohs codes instead. Malignant lesion excisions are bundled into the Mohs procedure and are not separately reportable. Step 3: Calculate the Total Excised Diameter Once the anatomical category is chosen, code selection is based on the excised diameter. CPT® defines this as the greatest clinical diameter of the lesion plus the narrowest margins required for complete excision. Use this equation for calculation purposes: For the opening scenario, a 2.0 cm neck melanoma with a 0.5 cm margin on both sides results in an excised diameter of 3.0 cm: 2 cm + (2 x 0.5 cm) = 3.0 cm. Report the excision with 11623 (Excision, malignant lesion including margins, scalp, neck, hands, feet, genitalia; excised diameter 2.1 to 3.0 cm). If margins are asymmetrical, use the narrowest required margin. A 1.0 cm lesion excised with margins ranging from 2.0 cm to 2.5 cm is calculated as 1.0 cm + (2 x 2.0 cm) = 5.0 cm. Handling asymmetric lesions: If a lesion is irregular or oblong (for example, 2.0 cm x 1.0 cm), use the maximum width as the base lesion measurement (2.0 cm). Coding tip: Report each lesion excision separately. If multiple lesions fall within the same excision borders, add the lesion lengths and twice the narrowest margin to calculate a single excised diameter, then report one code. Step 4: Evaluate the Wound Closure Under CPT® guidelines, the primary excision code includes the following: If the defect requires more than simple closure, report the repair code in addition to the excision code without a modifier. Intermediate repair involves layered closure of subcutaneous tissue and nonmuscle superficial fascia plus closure of the epidermis and dermis. It includes limited undermining (distance less than the maximum width of the defect). Complex repair is a layered closure plus techniques such as extensive undermining (distance greater than or equal to the maximum width of the defect), debridement of wound edges, or retention sutures. If the surgeon performs an adjacent tissue transfer (ATT) or rearrangement (such as a Z-plasty, W-plasty, VY-plasty, rotation flap, or advancement flap) to close the defect, the malignant lesion excision code is bundled into the ATT code and not separately reported. Double defects: An ATT flap may leave a secondary donor-site wound that requires an additional flap or skin graft to close. Report the primary ATT code first (bundling the lesion excision), followed by the additional graft or ATT code appended with modifier 51 (Multiple procedures). However, payer policies may require modifier 59 (Distinct procedural service) instead. Step 5: Append Modifiers Report each lesion excision separately when the physician performs multiple lesion excisions. Same anatomic code family: When both excisions fall within the same code series, report the code with the highest relative value unit (RVU) first with no modifier. According to CPT® Assistant, July 2023, append modifier 59 to the additional lesion excision. Here’s a coding example: However, you don’t need modifier 59 if you are coding for excisions in different anatomic code families. Multiple repairs: For the same complexity (for example, two complex repairs) in the same anatomical site, add the repair lengths in centimeters and report a single repair code. For different complexities or sites, report each separately and append modifier 59 to the lower RVU repair code(s). Biopsies with excisions: Tissue collection for pathology is inherent to lesion excision codes, so you cannot report a biopsy separately with a therapeutic excision. Report a separate integumentary system biopsy code only if the physician biopsied a distinct lesion, with modifier 59 appended. Staged re-excisions: For same-session re-excision, report a single CPT® code for the greatest excised diameter. If the patient returns during the postoperative global period of the primary excision, report an excision code based on the re-excision diameter appended with modifier 58 (Staged or related procedure or service by the same physician or other qualified health care professional during the postoperative period). Same-day E/M: Append modifier 25 (Significant, separately identifiable evaluation and management service by the same physician or other qualified health care professional on the same day of the procedure or other service) to a separate, significant evaluation and management (E/M) service performed by the same provider on the same date as the excision. Documentation must support that the E/M service is distinct and beyond the work of the excision. SLNB crossover: When a physician performs a sentinel lymph node biopsy (SLNB) during the same session as a melanoma excision, both procedures are separately reportable. SLNB codes include the following: No National Correct Coding Initiative (NCCI) Procedure-to-Procedure (PTP) edits exist between SLNB codes and malignant excision codes, so you don’t need modifier 59. Report 38792 (Injection procedure; radioactive tracer for identification of sentinel node) for the tracer injection or 78195 (Lymphatics and lymph nodes imaging) for lymphoscintigraphy, but do not report both codes together, as 78195 includes the injection work. You’ll report +38900 (Intraoperative identification (eg, mapping) of sentinel lymph node(s) includes injection of non-radioactive dye, when performed (List separately in addition to code for primary procedure)) for intraoperative mapping with nonradioactive dye. Code pathological examination per specimen; examples include the following: Coding tip: When the physician biopsies both superficial and deep axillary nodes through the same incision at the same session, report only the deep excision code per CPT® Assistant, Volume 18, Issue 9. Step 6: Pinpoint the Pathology Codes Harvesting and placing an excised specimen into a fixative for pathological examination is included in the malignant lesion excision code. The pathologist reports the pathological examination separately using an appropriate skin specimen pathology code. Pathology is coded per specimen based on diagnosis; examples include the following: Importance of containers: To bill pathology per specimen, each specimen should be submitted in a separately identified container for independent examination and diagnosis. Medical necessity must support separate examination. According to the Medicare National Correct Coding Initiative Policy Manual, multiple lesions treated as a single specimen are not separately reportable. Slide review bundle: Per Medicare NCCI coding guidelines, if a physician examines pathology slides for an already-excised lesion to determine if more surgery is needed, slide review is bundled into the appropriate E/M code. The provider cannot report surgical pathology consultation codes alongside the E/M service. Conclusion Accurately coding melanoma excisions requires evaluating multiple elements: lesion classification (benign or malignant), the deepest tissue layer involved (integumentary vs. musculoskeletal), anatomical grouping, excised diameter, closure complexity, and applicable modifiers. Awareness of which services are and are not separately reportable prevents bundling errors. Working step by step through these variables helps you determine the correct code and avoid claim denials. Angela Halasey, BS, CPC, CCS, Contributing Writer
Coding tip: If the physician didn’t record a measurement, assign the lowest-level code in the anatomical grouping (excised diameter of 0.5 cm or less). A provider query may be needed for pre-excision measurements.
We’ve covered how to calculate the excised area, but how do you determine whether to use an integumentary or a musculoskeletal excision code? Per AHA Coding Clinic® for HCPCS, Volume 22, Issue 1, “Code assignment is based on the lesion’s deepest layer.” Follow this advice when selecting a code:
