In Vivo Reflectance Confocal Microscopy

Reflectance confocal microscopy (RCM) imaging received Category I Current Procedural Terminology (CPT) codes by the Centers for Medicare & Medicaid Services in January 2016 and can now be submitted to insurance companies with reimbursement comparable to a skin biopsy or a global skin pathology service.¹ This fairly new technology is a US Food and Drug Administration–cleared noninvasive imaging modality that provides high-resolution in vivo cellular images of the skin. It has been shown to be efficacious in differentiating benign and malignant skin lesions, increasing diagnostic accuracy, and reducing the number of unnecessary skin biopsies that are performed. In addition to skin cancer diagnosis, RCM imaging also can help guide management of malignant lesions by detecting lateral margins prior to surgery as well as monitoring the lesion over time for treatment efficacy or recurrence. The potential impact of RCM imaging is tremendous, and reimbursement may lead to increased use in clinical practice to the benefit of our patients. Herein, we present a brief review of RCM imaging and reimbursement as well as the benefits and limitations of this new technology for dermatologists.

Reflectance Confocal Microscopy

In vivo RCM allows us to visualize the epidermis in real time on a cellular level down to the papillary dermis at a high resolution (×30) comparable to histologic examination. With optical sections 3- to 5-µm thick and a lateral resolution of 0.5 to 1.0 µm, RCM produces a stack of 500×500-µm² images up to a depth of approximately 200 µm.^2,3 At any chosen depth, these smaller images are stitched together with sophisticated software into a block, or mosaic, increasing the field of view to up to 8×8 mm². Imaging is performed in en face planes oriented parallel to the skin surface, similar to dermoscopy.

Current CPT Guidelines and Reimbursement

The CPT codes for RCM imaging provide reimbursement on a per-lesion basis and are similar to those used for skin biopsy and pathology (Table).¹ Codes 96931 through 96933 are used for imaging of a single lesion on a patient. The first code—96931—is used when image acquisition, interpretation, and report creation are carried out by a single clinician. The next 2 codes are used when one clinician acquires the image—96932—comparable to the technical component of a pathology code, while another reads it and creates the report—96933—similar to a dermatopathologist billing for the professional component of a pathology report. For patients presenting with multiple lesions, the next 3 codes—96934, 96935, and 96936—are used in conjunction with the applicable first code for each additional lesion with similar global, technical, and professional components. Because these codes are not in the radiology or pathology sections of CPT, a single code cannot be used with modifier -TC (technical component) and modifier -26, as they are in those sections.

The wide-probe VivaScope 1500 (Caliber I.D., Inc) currently is the only confocal device that can be reported with a CPT code and routinely reimbursed. The handheld VivaScope 3000 (Caliber I.D., Inc) can only view a small stack and does not have the ability to acquire a full mosaic image; it is not covered by these codes.

Images can be viewed as a stack captured at the same horizontal position but at sequential depths or as a mosaic, which has a larger field of view but is limited to a single plane. To appropriately assess a lesion, clinicians must obtain a mosaic that needs to be assessed at multiple layers for a diagnosis to be made because it is a cross-section view.

Diagnosis

Studies have demonstrated the usefulness of RCM imaging in the diagnosis of a wide range of skin diseases, including melanoma and nonmelanoma skin cancers, infectious diseases, and inflammatory and autoimmune conditions, as well as wound healing and skin aging. Reflectance confocal microscopy imaging is not limited to the skin; it can be used to evaluate the hair, nails, oral mucosa, and other organs.

According to several studies, RCM imaging notably increases the diagnostic accuracy and detection rate of skin cancers over clinical and dermoscopic examination alone and therefore can act as an aid in differentiating lesions that are benign versus those that are suspicious and should be biopsied.

Reflectance confocal microscopy has been shown to have a mean sensitivity of 94% (range, 92%–96%) and specificity of 83% (range, 81%–84%) for all types of skin cancer when used with dermoscopy.⁴ In particular, for melanocytic lesions that are ambiguous on dermoscopy, RCM used in addition to dermoscopy increases the mean sensitivity and specificity for melanoma diagnosis to 93% (range, 89%–96%) and 76% (range, 68%–83%), respectively.⁵ Although these reported sensitivities are comparable to dermoscopy, the specificity is superior, especially for detecting hypomelanotic and amelanotic melanomas, which often lack specific features on dermoscopy.^6-8

The combination of RCM with dermoscopy has reduced the number of unnecessary excisions of benign nevi by more than 50% when compared to dermoscopy alone.⁹ One study showed that the number needed to treat (ie, excise) a melanoma decreased from 14.6 with dermoscopy alone to 6.8 when guided by dermoscopy and RCM imaging.⁹ In a similar study, the number needed to treat dropped from 19.41 with dermoscopy alone to 6.25 with dermoscopy and RCM.¹⁰

These studies were not looking to evaluate RCM as a replacement test but rather as an add-on test to dermoscopy. Reflectance confocal microscopy imaging takes longer than dermoscopy for each lesion; therefore, RCM should only be used as an adjunctive tool to dermoscopy and not as an initial screening test. Consequentially, a dermatologist skilled in dermoscopy is essential in deciding which lesions would be appropriate for subsequent RCM imaging.