Dermatology Coding Alert

Check your clinical solutions against our expert answers.

How is your Mohs coding acumen? Read on for our expert solutions to the scenarios you saw earlier in this issue.

Answer 1: A. You would 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 dermatologist 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 CPT® 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 CPT® 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.

Go deeper: For more on this ICD-10 transition, see “ICD-10: Specify Malignant Melanoma or Melanoma In Situ” in Vol. 10 No. 9 of Dermatology Coding Alert.

Answer 2: D. This procedure was a two-stage procedure:

• Stage 1: The first six tissue blocks, which had margins that were not clear

• Stage 2: The next three tissue blocks, which had clear margins.

For stage 1, CPT^® code 17311 would cover the first five tissue blocks, and 17315 for the one additional block in that stage.

For stage 2, CPT^® add-on code 17312 covers all three tissue blocks in that stage.

Dx: Link the codes to ICD-9 code 173.32 (Squamous cell carcinoma of skin of other and unspecified parts of face) – or, after Oct. 1, 2015, one of these ICD-10 codes:

• C44.320 – Squamous cell carcinoma of skin of unspecified parts of face

• C44.321 – … of skin of nose

• C44.329 – … of skin of other parts of face.

Answer 3: D. To report Mohs, the physician needs to work as both a dermatologist and a pathologist. In this case, the pathological analysis was outsourced to a hospital.

You should report the first 1.8 cm excision with CPT^® 11642 (Excision, malignant lesion including margins, face, ears, eyelids, nose, lips; excised diameter 1.1 to 2.0 cm) and 11643 (... excised diameter 2.1 to 3.0 cm) for the 2.4 cm excision, since there were two excisions on the same date of service, says Pamela Biffle, CPC, CPC-P, CPC-I, CPCO, owner of PB Healthcare Consulting and Education Inc. in Austin, Texas. It is important to alert the provider the importance of documenting the surgical plan in each procedure note. More specifically, a notation that potential additional excisions would be performed within a short period if the pathology results were adverse. When documented properly, you may attach modifier 58 (Staged or related procedure or service by the same physician or other qualified health care professional during the postoperative period) to 11643.

Answer 4: No. Regardless of whether the reconstructive surgeon is new to the case or is the same person who performed the Mohs, report separate reconstruction codes for flaps or grafts.

In this scenario, the dermatologist uses two advancement flaps to repair a 2.4-cm excision. Remember: Even though he uses two flaps, there is only one defect site and therefore only one applicable code, 14060 (Adjacent tissue transfer or rearrangement, eyelids, nose, ears, and/or lips; defect 10 sq cm or less).

Look out: You may face challenges in repair approval because some carriers will initially classify as cosmetic a closure following a multi-step excision. To make your case for medical necessity, be sure to link the cancer diagnosis to your reconstruction code. In this case, you would use 140.1 (Malignant neoplasm of lower lip, vermilion border) to report the squamous cell carcinoma.