Pathology/Lab Coding Alert

Question: The dermatopathologist removes a basal cell carcinoma from the central portion of the patient’s forehead. Specifically, he removes the carcinoma (first stage) and divides it into four tissue blocks for examination. Upon microscopic examination, the dermatopathologist finds the margins are clear of carcinoma. What CPT^® code(s) should we report for this procedure?

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Answer: You should report one unit of 17311 (Mohs micrographic technique, including removal of all gross tumor, surgical excision of tissue specimens, mapping, color coding of specimens, microscopic examination of specimens by the surgeon, and histopathologic preparation including routine stain[s] [e.g., hematoxylin and eosin, toluidine blue], head, neck, hands, feet, genitalia, or any location with surgery directly involving muscle, cartilage, bone, tendon, major nerves, or vessels; first stage, up to 5 tissue blocks) for this scenario, which is a first-stage procedure.

The Mohs codes differ based on:

• The location of the lesion(s)

• The stage of the procedure

• The number of tissue blocks.

So if the dermatopathologist prepares four blocks during the first stage of a removal of a lesion from the neck, you would report 17311. If he went on to perform a second stage, you would also report add-on code +17312 (…each additional stage after the first stage, up to 5 tissue blocks [List separately in addition to code for primary procedure]). If, during any stage, he prepared more than five blocks, you would report add-on code +17315 (…each additional block after the first 5 tissue blocks, any stage [List separately in addition to code for primary procedure]) for each additional block.

Dx: Link the procedures to ICD-9 code 173.31 (Basal cell carcinoma of skin of other and unspecified parts of face) for services rendered before Oct. 1, 2015. After that date, when ICD-10 takes effect, you would report one of the following:

• C44.310 – Basal cell carcinoma of skin of unspecified parts of face

• C44.311 – … of skin of nose

• C44.319 – … of skin of other parts of face.