General Surgery Coding Alert

Question: I've been hearing contradictory advice on how to measure lesions for removal. Should I include the margins? Do I measure the lesion before or after sending the sample to pathology?


South Carolina Subscriber


Answer: CPT changed its guidelines for measuring lesions in 2003. Since that time, to determine the total excised diameter, you must calculate the lesion diameter at its widest point (the crucial measurement under the pre-2003 guidelines), plus twice the width of the margin at its narrowest point.

For example, the surgeon excises an irregularly shaped, malignant lesion from a patient's left shoulder. The lesion measures 2.5 cm at its widest. To ensure removal of all malignancy, the surgeon allows a margin of at least 1.5 cm on all sides. In this case, add the size of the lesion (2.5 cm) and double the width of the narrowest margin (1.5 cm + 1.5) for a total of 5.5 cm (2.5 + 1.5 + 1.5 = 5.5). Therefore, you should report 11606 (Excision, malignant lesion including margins, trunk, arms, or legs; excised diameter over 4.0 cm).

To answer your second question: The correct time to measure the lesion is prior to excision. The pathology report will not provide an accurate measurement because lesions shrink when placed in formaldehyde. Relying on the pathology report will mean smaller measurements and a consequent loss in compensation. Similarly, often the excision site will be larger than the actual incision if the edges of the wound are under tension.