Dermatology Coding Alert

Question: If our dermatologist removes a sebaceous cyst from the back that measures 2.5 x 1. 5 x 0.5 cm, what dimension should we use to select the proper skin lesion code? Do you determine the size the same way if it's a lipoma, and how should we measure for repair codes?

Texas Subscriber

Answer: Whether the dermatologist removes a cyst or lipoma with the lesion measurements you gave, you should select the code based on the largest dimension (2.5 cm). If the dermatologist also documents the width of the narrowest margin, however, you could add that to the overall excision size. In other words, not documenting the margin means you're leaving money on the table.

Add margins: Whenever the dermatologist excises a skin or soft tissue benign or malignant neoplasm, you should determine the size for coding purposes based on the largest lesion diameter plus two times the narrowest margin. Looking at the example you gave, let's see how a narrowest margin of 0.5 cm impacts your code selection:

Cyst without margin -- 2.5 cm codes to 11403 (Excision, benign lesion including margins, except skin tag [unless listed elsewhere], trunk, arms or legs; excised diameter 2.1-3.0 cm)

Cyst with margin -- 2.5 cm + 2 x 0.5 cm = 3.5 cm codes to 11404 (... excised diameter 3.1 to 4.0 cm)

Subcutaneous lipoma without margin -- 2.5 cm codes to 21930 (Excision, tumor, soft tissue of back or flank, subcutaneous; less than 3 cm)

Subcutaneous lipoma with margin -- 2.5 cm + 2 x 0.5 cm = 3.5 cm codes to 21931 (...3 cm or greater).

Measure repair differently: Skin lesion excision codes include simple repair, and soft tissue tumor excision codes include both simple and intermediate repair. If your dermatologist performs an intermediate or complex repair for skin or a complex repair for soft tissue, you should use different criteria to code the repair size than you used for the lesion size. What you need to know for the repair is the greatest length of the wound, which is likely greater than the lesion excision itself because dermatologists may create elliptical wounds because they're easier to close.

You should identify the total length of the repair and choose the intermediate repair code that matches that length.

For instance: In the prior lesion-size example, the widest diameter of the lesion plus the narrowest margin is 3.5 cm. But if the dermatologist used an elliptical excision, the length of the repair might be 6 cm. If the dermatologist performed a layered closure, you should report 12032 (Repair, intermediate, wounds of scalp, axillae, trunk and/or extremities [excluding hands and feet]; 2.6 to 7.5 cm) in addition to the excision code.