Q&A: Selecting a Follow-up Excision Code
Question: A patient had a biopsy done at another facility by a different provider. The biopsy showed squamous cell carcinoma, and our dermatologist performed a further excision to obtain clear margins at that site. The path report for this follow-up excision came back as actinic keratosis. Would the proper CPT® coding be 11603 (based on the original diagnosis of squamous cell carcinoma) or 11403 (based on the follow-up result of actinic keratosis)?
Answer: Under most circumstances, you absolutely cannot use the “malignant” code and/or diagnosis unless the malignancy has been confirmed by pathology. In this case, however, the previous excision and biopsy did confirm this, and the re-excision was done to obtain clear margins. The assumption is that both the diagnosis and procedure code are for the malignancy.
Per the May 2012 CPT Assistant, even if the subsequent pathology comes back with a different diagnosis, the further excision should be linked to the original (malignant) diagnosis:
In general, the selection of the appropriate excision code is determined by three parameters: location, maximum excised diameter (which includes the margin), and lesion type (ie, benign or malignant). When the lesion is clearly benign (eg, cyst, lipoma, prior biopsy of benign neoplasm), the excision can be coded as benign at the time of surgery (11400-11471). When there is a prior biopsy showing malignancy, the excision can be coded as malignant at the time of surgery (11600-11646).
Coding excision of a cutaneous lesion pending pathology (eg, lesion of unspecified behavior) as malignant before pathology is available could result in incorrect coding if the lesion is found to be benign on histopathologic examination. Therefore, if the lesion is not clearly benign or malignant, coding and billing should be delayed until the pathology has been confirmed.
Note the final line in the first paragraph, “When there is a prior biopsy showing malignancy, the excision can be coded as malignant at the time of surgery (11600-11646).” In this case, you would report 11603 Excision, malignant lesion including margins, trunk, arms, or legs; excised diameter 2.1 to 3.0 cm, rather than the benign excision code 11403 Excision, benign lesion including margins, except skin tag (unless listed elsewhere), trunk, arms or legs; excised diameter 2.1 to 3.0 cm.