Documentation for Mohs Surgery

In 2013, the Centers for Medicare and Medicaid Services (CMS) issued a guidance to reduce reimbursement issues for Mohs micrographic surgery (MMS).¹ One crucial question that remains is when and if these documentation guidelines will be formally implemented. The guidelines outlined by the CMS currently are regarded as suggestions until Medicare contractors adopt them into the local coverage determinations (LCDs).

Key Documentation Guidelines

To reduce MMS reimbursement issues, documentation in the patient’s medical record should support the medical necessity of the procedure and reflect the number and anatomic locations of specimens taken and the reason for the procedure should be clearly communicated. The specific tumor type also should be approved for treatment with MMS in the respective LCD.

Nonphysician providers are not authorized by Medicare to perform MMS. To ensure proper coding, both surgery and pathology must be performed by a single physician and should be supported by documentation in the patient’s medical record (eg, relevant chart notes should be made under the provider’s signature). These documentation guidelines are not new but are included in the CMS guidance to reiterate their importance in reducing MMS reimbursement issues.

Per customary clinical practice, the CMS guidance specifies that MMS documentation should include gross description of the tissue removed, including the location, number, and size of the lesions, as well as how many specimens were removed for each stage. However, the guidance diverges from routine MMS documentation requirements in its emphasis on providing a histologic description of the tissue removed. The guidance suggests that the depth of tumor invasion, pathologic pattern, cell morphology (which is not typically specified for skin cancers), and, if present, the existence of perineural invasion or scar tissue should be documented. If these features are constant across stages, they only need to be noted for the first stage.

Adapting Guidelines for Clinical Practice

The CMS guidance may create some conundrums for physicians regarding MMS documentation; for instance, if a tumor is cleared in one stage, as is often the case, no tumor will be seen on glass slides prepared to assess tissue margins during the procedure and therefore documentation of characteristics like depth and pattern will be impossible. Similarly, cell morphology is not a feature that usually is relevant for most squamous and basal cell carcinomas, although it may be useful in certain unusual instances, such as in cases of rare tumors with particular histologic features that may influence management and/or prognosis. When in doubt regarding the appropriate documentation method for MMS, the surgeon should use his or her best judgment based on clinical experience rather than simply following guidelines that may not be applicable.

Final Thoughts

The CMS guidance serves as a reminder of the documentation requirements for MMS and extends current practice by suggesting a detailed microscopic description of the removed tissue. The American Academy of Dermatology has developed a guide to help Mohs surgeons provide the necessary documentation without creating cumbersome chart notes.² Mohs surgeons should consult the most recent version of the LCD that applies to their geographic area to determine if the new documentation guidelines have been adopted.