In October 2020, Medicare released an updated guidance to reduce Mohs micrographic surgery (MMS) reimbursement issues,1 which initially was released in 2013. This guidance defines the latest performance and documentation requirements that Medicare requires for MMS. Understanding these requirements and making sure that your Mohs surgical reports have all the needed documentation details are critical because auditors from not only Medicare Administrative Contractors (MACs) but also private insurers and Medicare Advantage plans have adopted these standards and will deny payment for Mohs surgical codes if they are not met. This article provides a review of the updated Medicare requirements to make sure your MMS procedure notes are audit proof.
Notes Must Indicate Mohs Is the Most Appropriate Treatment
I review many of my colleagues’ Mohs notes and can tell you that some of the requirements laid out in the updated guidance typically are already reported by Mohs surgeons in their notes, including the location, number, and size of the lesion or lesions treated and the number of stages performed. However, there are some new requirements that often are not reported by Mohs surgeons that now need to be included. The guidance indicates the following:
The majority of skin cancers can be managed by simple excision or destruction techniques. The medical record of a patient undergoing MMS should clearly show that this procedure was chosen because of the complexity (eg, poorly defined clinical borders, possible deep invasion, prior irradiation), size or location (eg, maximum conservation of tumor-free tissue is important). Medicare will consider reimbursement for MMS for accepted diagnoses and indications, which you must document in the patient’s medical record as being appropriate for MMS and that MMS is the most appropriate choice for the treatment of a particular lesion.1
In my experience, most Mohs notes include some statement that the skin cancer treated is appropriate based on the Mohs appropriate use criteria (AUC) or the AUC score. However, notes should make clear not just that the lesion treated is “appropriate” for MMS but also that it is the most appropriate treatment (eg, why the lesion was not managed by standard excision or destruction technique).
Mohs Surgeon Must Perform the Surgery and Interpret Slides
The updated guidance clearly indicates that MMS may only be performed by a physician who is specifically trained and highly skilled in Mohs techniques and pathologic identification: “Medicare will only reimburse for MMS services when the Mohs surgeon acts as both surgeon and pathologist.”1 Mohs micrographic surgery codes may not be billed if preparation or interpretation of the pathology slides is performed by a physician other than the Mohs surgeon. Operative notes and pathology documentation in the patient’s medical record should clearly show that MMS was performed using an accepted MMS technique in which the physician acts in 2 integrated and distinct capacities—surgeon and pathologist—thereby confirming that the procedure meets the definition of the Current Procedural Terminology code(s).
Furthermore, the Mohs operative report should detail “the number of specimens per stage.”1 I interpret this statement to indicate that the Mohs surgeon should document the number of tissue blocks examined in each stage of Mohs surgery. For example, a statement in the notes such as “the specimen from the first Mohs stage was oriented, mapped, and divided into 4 blocks” should suffice to meet this requirement.
Histologic Description Must Be Included in Mohs Notes
Medicare will require the Mohs surgeon to document “the histology of the specimens taken. That description should include depth of invasion, pathological pattern, cell morphology, and, if present, perineural invasion or presence of scar tissue.”1 Although this histologic description requirement appears daunting, it is common for Mohs surgeons to indicate their pathologic findings on their Mohs map such as “NBCC” next to a red area to indicate “nodular basal cell carcinoma visualized.” A template-based system to translate typical pathologic findings can be employed to rapidly and accurately populate a Mohs note with histologic description such as “NBBC=nodular aggregates of palisaded basaloid epithelial tumor arising from the epidermis forming a palisade with a cleft forming from the adjacent mucinous stroma extending to the mid dermis. Centrally the nuclei become crowded with scattered mitotic figures and necrotic bodies evident.”
Recent Improvement for 1-Stage Mohs Surgeries
The most notable improvement in the 2020 MMS reimbursement requirements vs the prior version is that, “If tumor is visualized on stage one, you must describe the histology of the specimens taken.”1 This indicates that if no tumor is visualized in the first stage, then no description of the tumor is possible or necessary. This is a much-needed improvement, as I have observed that some auditors have denied 1-stage Mohs surgeries due to lack of tumor histology description.
Final Thoughts
Overall, the updated Medicare guidance provides important details in the requirements for performance and documentation of Mohs surgery cases. However, additional critical information will be found in Mohs coverage policies and local coverage determinations (LCDs) from MACs and private insurers.2-4 Each LCD and insurer Mohs payment policy has unique wording and requirements. Coverage of MMS for specific malignant diagnoses, histologic subtypes, locations, and clinical scenarios varies between LCDs; most are based directly on the Mohs AUC, while others have a less specific coverage criteria. To understand the specific documentation and coverage requirements of the MAC for a particular region or private insurer, Mohs surgeons are encouraged to familiarize themselves with the Mohs surgery LCD of their local MAC and coverage policies of their insurers and to ensure their documentation substantiates these requirements. Making sure that your MMS documentation is accurate and complies with Medicare and insurer requirements will keep you out of hot water with auditors and allow reimbursement for this critical skin cancer procedure.