Billing and Coding: Mohs Micrographic Surgery

Italicized font represents CMS national language/wording copied directly from CMS Manuals or CMS Transmittals. Contractors are prohibited from changing national language/wording.

Social Security Act
Title XVIII of the Social Security Act (SSA):

• Title XVIII of the Social Security Act, Sections 1861 [s] [1], only physicians (MD/DO) may perform this procedure.
• Title XVIII of the Social Security Act, §1862(a)(1)(A) states that no Medicare payment shall be made for items or services which are not reasonable and necessary for the diagnosis or treatment of illness or injury.
• Title XVIII of the Social Security Act, Section 1833(e), this section prohibits Medicare payment for any claim which lacks the necessary information to process the claim.

CMS Publications:

• CMS Pub. 100-02, Medicare Benefit Policy Manual, Chapter 15 – Covered Medical and Other Health Services, §30 - Physician Services.
• CMS Pub. 100-02, Medicare Benefit Policy Manual, Chapter 16 – General Exclusions From Coverage, §120 - Cosmetic Surgery.
• CMS Pub. 100-04, Medicare Claims Processing Manual, Chapter 12 – Physicians/Nonphysician Practitioners, §40-40.6, Surgeons and Global Surgery.
• CMS Pub. 100-04, Medicare Claims Processing Manual, Chapter 12 – Physicians/Nonphysician Practitioners, §60, Payment for Pathology Services.
• CMS Transmittal No. 434, Pub. 100-04, Medicare Claims Processing Manual, Change Request #3458, January 14, 2005, Addition of CLIA Edits to Certain Health Care Procedure Coding System (HCPCS) Codes for Mohs Surgery.
• CMS Transmittal No, 857, effective date October 3, 2018 Change Request 10901 Local Coverage Determinations (LCDs) Implementation date January 8, 2019.

The billing and coding information in this article is dependent on the coverage indications, limitations and/or medical necessity described in the associated LCD L35494 Mohs Micrographic Surgery.

The medical records should clearly show that Mohs surgery was chosen because of the complexity, size and/or location of the lesion and why other approaches are not medically necessary and reasonable. The operative notes and pathology documentation in the patient’s medical record must clearly show that Mohs micrographic surgery was performed using accepted Mohs technique, with the same physician performing both the surgical and pathology services. The notes should also contain the location, number, and size of the lesion(s), the number of stages performed, and the number of specimens per stage. Denied claims may be appealed and providers can submit documentation to support the service.

The Current Procedural Terminology (CPT)/Healthcare Common Procedure Coding System (HCPCS) code(s) may be subject to National Correct Coding Initiative (NCCI) edits. This information does not take precedence over NCCI edits. Refer to NCCI for correct coding guidelines and specific applicable code combinations prior to billing Medicare.

CPT codes 17311-17315 are reserved for the surgeon who removes a lesion, prepares, and interprets the slides. Select skin biopsy/excision services and pathology services are part of the MOHS surgery and bundled into 17311-17315. Refer to the NCCI Manual and CPT manual for additional information.

MOHS surgery includes the pathologic examination of the specimen performed by the surgeon and should not be reported separately. There may be instances when a MOHS surgeon submits a specimen(s) derived from the procedure for pathologic examination to another physician (i.e., pathologist) for either frozen or permanent section. In those situations, the service is not considered a MOHS service and pathology service may be reported by the performing pathologist. The surgeon should report for excision and repair using appropriate codes (Reference American Medical Association [AMA] CPT Professional Edition)

• It is NOT appropriate to report modifier -59 when the biopsy and MOHS surgery are performed on the same lesion, in the same operative session and on the same date of service. However, if a suspected skin cancer is biopsied for pathologic diagnosis prior to proceeding to MOHS micrographic surgery, the biopsy and frozen section pathology may be reported separately using modifier -59 to distinguish the diagnostic biopsy from the definitive MOHS surgery Refer to the NCCI Manual and CPT manual for additional information.
  • Modifier -59 should only be appended to the pathology codes, by the MOHS surgeon, if a biopsy is performed on a completely separate lesion that does not involve the MOHS surgery; however, MOHS surgery and pathology service may be reported when tissue separate from the tissue examined during the MOHS surgery is submitted for subsequent formalin-fixed processing and histopathologic examination (i.e., the submitted specimen originates from the same operative site or from a different operative site but is not the same tissue processed during the MOHS surgery). Refer to the NCCI Manual and CPT manual for additional information.
  • There may be rare instances where a biopsy and pathology must occur on the same date as a MOHS procedure. In these instances, skin biopsy CPT codes and the pathology CPT codes may be reported with the -59 modifier appended if:
    • The lesion for which MOHS is planned has not been biopsied within the previous 60 days, or
    • If the surgeon cannot obtain a pathology report from the referring physician with a reasonable effort, or
    • The biopsy is performed on a lesion that is not associated with the MOHS surgery. For example: If a biopsy is performed prior to the MOHS surgery for a diagnostic purpose, the biopsy can also be performed. Modifier -59 or -58 would be appended to distinguish the diagnostic biopsy from the definitive MOHS surgery Refer to the NCCI Manual and CPT manual for additional information.
• When it is appropriate to report modifier -59, the modifier should be reported on the same line as the biopsy procedure codes. It should NOT be reported on the same line as the MOHS procedure.

The appropriate MOHS surgery code should be reported with the appropriate quantities for the specimens mapped in the days/units field.

CPT code 17312 should be reported for additional stages with the first stage code 17311.
CPT code 17314 should be reported for additional stages with the first stage code 17313.
CPT code 17315 may be used to report each block after the first 5 blocks for any single stage.

All surgical procedures performed in the same operative session should be reported on the same claim.

Multiple instances of CPT codes 17312 and 17314 should not be reported on separate claim lines. The services should be totaled and entered as a single item with the appropriate number of units of service.

Please note that these codes refer to the number of blocks, not number of slides.

If a MOHS procedure is performed on a completely separate lesion on the same date of service, each first stage (CPT code 17311 or 17313) code should be reported on a separate claim line with a -59 modifier signifying a separate and distinct lesion. If additional stages are required on the additional lesion, report the second stage codes (CPT code 17312 or 17314) on separate claim lines with a -59 modifier (Reference NCCI Initiative Modifiers: Modifier 59 Fact Sheet).

Documentation Requirements

1. All documentation must be maintained in the patient’s medical record and made available to the contractor upon request.
2. Every page of the record must be legible and include appropriate patient identification information (e.g., complete name, dates of service[s]). The documentation must include the legible signature of the physician or non-physician practitioner responsible for and providing the care to the patient.
3. The submitted medical record must support the use of the selected ICD-10-CM code(s).
4. The submitted CPT/HCPCS code must describe the service performed. The medical record documentation must support the medical necessity of the services as stated in this policy.
5. Procedures that exceed the medical need are not reasonable and necessary (not a Medicare covered service), therefore, documentation (pre-procedure E/M note and/or post-procedure operative notes) must address (a) why the lesion will not be (was not) managed by standard excision or destruction technique and (when applicable) (b) why (when utilized or referred to a plastic surgeon) procedures for complex repair, adjacent tissue transfer or rearrangement, flap, or graft codes are employed.
6. The physician must document in the patient’s medical record that the diagnosis is appropriate for MMS and that MMS is an appropriate choice as the treatment of the particular lesion. The options for care (both the primary procedure options and repair options) must be discussed with the patient and clearly noted in the pre-procedure (or post procedure as appropriate) documentation. In summary, the minimal medical record documentation entails that the beneficiary was informed of their treatment options and explained the risks/benefits of the MMS technique and associated repair.
7. Though complexity of the lesion (poorly defined borders, suspected deep invasion, recurrent lesion, prior radiation), lesion size/location, and maximum conservation of healthy tissue are to be addressed in the preoperative medical record, the surgeon must document why the lesion will not be (was not) managed by excision or destruction technique.
8. Operative notes and pathology documentation in the patient’s medical record should clearly document that MMS was performed using accepted MMS technique, in which the physician acts in two integrated and distinct capacities: surgeon and pathologist (therefore confirming that the procedure meets the definition of the CPT code[s]).
9. Operative documentation should note: location, number, and size of the lesion(s); number of stages performed; number of specimens per stage.
10. Histology documentation must include the following:
    • First stage: if tumor present, depth of invasion; pathological pattern of the tumor; cell morphology; if present, note perineural invasion of scar tissue.
    • Subsequent stages: if the tumor characteristics are the same as in the first stage, note this fact only. If the tumor characteristics are different from the first stage, describe the differences.
11. Measurement of the primary lesion necessitating MMS and measurements in support of repair or related procedures (such as but not limited to adjacent tissue transfer/rearrangements, grafts/flaps) completing the MMS procedure and confirming the primary defect measurement or other relevant measurements should be verifiable. Documentation of the clinical tumor border definition may be accomplished by:
    • Preoperative photography with the skin stretched to delineate the visible clinical borders with or without debulking curettage (using a centimeter ruler or relation of size by another anatomic structure).
    • Postoperative photography to document the defect may also be considered, especially for small lesions that have a significant subepithelial component (i.e., tip of the iceberg phenomenon).
    • It is understood that photographic documentation may not be possible in a small percentage of cases because of technical difficulties.
12. When the surgical defect created by MMS requires reconstruction, it should be clear in the documentation that the reconstructive technique performed was an appropriate choice to preserve functional capabilities and to restore physical appearance.