Dermatology Coding Alert

Warning:  Length of incision doesn't equal excised diameter

When it comes to coding lesion excisions, when you take measurements is just as important as how you take them.
 According to CPT, to determine the appropriate lesion excision code, you must measure the lesion's diameter at its widest point and add to that measurement double the width of the narrowest margin.

Document Measurements Prior to Excision

Dermatologists should calculate and document the size of the lesion excision before removing the lesion and sending it to pathology for analysis. This is because the lesion's size will be smaller as soon as the first incision releases some of the tension on the skin, and the sample will likely shrink further when placed in formaldehyde. And, because codes for excision of benign (11400-11471) and malignant (11600-11646) lesions are "size-based," a shrunken sample will mean smaller reimbursement, too.

"Taking measurements at the appropriate time is a matter of both clinical and coding accuracy," says Michelle Logsdon, CPC, CCS-P, of Falcon Practice Management LLC, in Bayville, N.J.

Example: The dermatologist excises an irregularly shaped, malignant (as later determined by a pathology report: see below) lesion from just below the patient's right shoulder. The lesion measures 2 cm at its widest point. To ensure removal of all malignancy, the surgeon allows a margin of at least 1.5 cm on all sides.

To calculate the excised diameter, you should begin with the size of the lesion (2 cm) and add the width of the narrowest margin multiplied by 2 (1.5 x 2, or 3 cm total) for a total of 5 cm (2 + 3 = 5). In this case, therefore, you should report 11606 (Excision,
).

Possible problem: When calculating excision diameter, be careful not to confuse the length of the incision with the size of the excision. Often, the dermatologist will make an incision that is longer than the lesion because "the longer you make that ellipse, the flatter your scar is going to be," but this has no bearing on code selection, says Allan Wirtzer, MD.

Solution: Base your measurements on the actual size of the lesion before the dermatologist performs the excision and prior to sending it to pathology, not according to the size of the surgical wound left behind.

Wait for Path Report Before Choosing Diagnosis

Because CPT classifies lesions as either "benign" or "malignant," you should always wait for the pathology report before selecting ICD-9 or CPT codes to describe the types of lesions and excisions. CMS guidelines allow for this practice, which helps ensure claims' accuracy.

Although most dermatologists will know if the lesion is benign, "it's better to wait for the pathology report and be sure," Logsdon says.

Dx coding tip: Refer to the "table of neoplasms" in the Index to Disease portion of ICD-9 to locate an initial diagnosis for benign or malignant neoplasms. Always refer to the full definition in the Tabular List before settling on a final diagnosis, however.

Example: The dermatologist excises a 1.5-cm lesion from the patient's shoulder. Pathology confirms that the lesion is a primary malignancy.

To find a diagnosis, go first to the table of neoplasms and look for neoplasm of the skin, shoulder. When you find this entry, follow the column marked "primary" to arrive at a provisional diagnosis of 173.6. The tabular listing confirms that this diagnosis applies to "Other malignant neoplasm of skin; skin of upper limb, including shoulder."

Look to 59 for Multiple Excisions

You should treat each lesion excision as an individual and separate procedure, says Barbara J. Cobuzzi, MBA, CPC, CPC-H, CPC-P, CHCC, president of CRN Healthcare Solutions, a coding and reimbursement consulting firm in Shrewsbury, N.J. Therefore, you would not "add together" the excised diameters of multiple lesions as you would the lengths of multiple wounds for wound repair (12001-13160), for example.

You should, however, attach a verifiable diagnosis to each individual CPT code when reporting multiple excisions. In addition, you should append modifier 59 (Distinct procedural service) to the second and subsequent codes describing excisions at the same location to avoid duplication denials.

Example: The dermatologist removes three lesions, all from the left arm, with sizes 1 cm (benign), 1.5 cm (benign) and 2.5 cm (malignant). In this case, you should report:

• 11603 (Excision, malignant lesion including margins, trunk, arms or legs; excised diameter 2.1 to 3.0 cm) with 173.6

• 11402-59 (Excision, benign lesion including margins, except skin tag [unless listed elsewhere], trunk, arms or legs; excised diameter 1.1 to 2.0 cm; Distinct procedural service) with 216.6 (Benign neoplasm of skin; skin of upper limb, including shoulder)
 • 11401-59 (... excised diameter 0.6 to 1.0 cm) with 216.6.