Billing and Coding: Mohs Micrographic Surgery (MMS)

This Billing and Coding Article provides billing and coding guidance for Local
Coverage Determination (LCD) L34961, Mohs Micrographic Surgery (MMS). Please
refer to the LCD for reasonable and necessary requirements.  
  
 **Coding Guidance**  
  
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 Assistant, February 2014,
Volume 24, Issue 2, page 10).

  * 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 (Reference American Hospital Association [AHA] Coding Clinc, 2013, Volume 13, Number 3 and NCCI Chapter 3). 
    * 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). Reference AHA Coding Clinc, 2013, Volume 13, Number 3 and NCCI Chapter 3 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 (Reference AHA Coding Clinc, Volume 13, Number 3).

  * 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 AHA Coding Clinc, Volume 13, Number
3).  
  
A Clinical Laboratory Improvement Act (CLIA) certification number is required
on all claims submitted for Mohs surgery. The CLIA number should be submitted
in item 23 on the CMS 1500 claim form or the electronic equivalent.  
  
 **Other Information  
  
** **Other Comments  
  
** The medical record must clearly document and support the situations where
modifier -59 is appropriate.