Several technologies are currently available to aid in the evaluation and diagnosis of skin lesions, such as ultrasonography, in vivo reflectance confocal microscopy (RCM), ex vivo confocal microscopy, magnetic resonance imaging, spectroscopy, and optical coherence tomography, among others.

RCM is a recently introduced non-invasive imaging method that allows real-time skin examination with morphological assessment with in vivo cellular and nuclear resolution, without the need for fluorescent markers or tissue dyes.1

Image depth is limited to about 200 µm, which usually allows examination down to the papillary dermis. This depth routinely includes and allows examination of the dermal-epidermal junction (DEJ), which is generally located at 50 to 150 µm depth. For dermatologists and pathologists, the DEJ is of great interest, as most skin cancers originate in the basal layer and DEJ.2 However, this depth limit may hinder the observation of structures of interest for the evaluation of tumors in special areas such as the palmo-plantar surface, thick, hyperkeratotic, and ulcerated lesions.

The imaging analysis result depends on a long learning curve; however, for trained physicians, it is a sensitive and specific tool for the early detection of melanomas and other skin tumors. The main current indications for this type of examination are isolated assessment of dubious melanocytic lesions, investigation of pigmented or non-pigmented lesions suspected of skin cancer, and preoperative delimitation of excision margins or post-treatment follow-up.1,2

The main correlations between histopathological findings and RCM were first described in the 1990s.3,4 Since then, hundreds of articles have been published, showing the importance of RCM as a complementary tool in the diagnosis of melanoma and non-melanoma skin cancers. RCM is also used in the evaluation of normal skin, melanocytic nevi, and benign non-melanocytic lesions. The definition and terms related to RCM criteria were established by a consensus published in the medical literature in 2007 and updated in 2009.5,6 The standardization of RCM terminology for both melanocytic and non-melanocytic lesions was recently published in the English language, after a systematic review of the terms used to describe the main findings in RCM in original articles during the years 1995‒2017.7,8

Despite the numerous publications on RCM in English and the growing number of Brazilian dermatologists using this new tool, to date, there is no official terminology in Portuguese. The objective of the present study is to propose a terminology in Brazilian Portuguese for the description of the RCM exam, generating the first Brazilian consensus on terms related to normal skin and cutaneous tumors, which will allow Brazilian dermatologists to communicate more accurately and homogeneously, facilitating the exchange of information and knowledge in the area.

Ten specialists (nine dermatologists and one dermatopathologist) were selected according to their publications, participation in studies, and years of RCM technique use in the diagnosis of skin tumors. The selection included professionals from different institutions and different states of Brazil, determining heterogeneity of the group, a crucial characteristic in this type of study.

Participants were invited as panelists via electronic communication and their participation in this project was completely voluntary and had no financial support.

The modified Delphi method was used for the creation of the consensus,9 in 3 steps. As a support tool for data collection, electronic forms were generated using the Google Forms tool (normal skin, melanocytic lesions, and non-melanocytic lesions). The forms were sent to each participant by e-mail and the responses were received anonymously.

In the first step, a list of terms used in RCM for normal skin and melanocytic and non-melanocytic tumors was created, encompassing benign and malignant lesions, based on related terms in the English language used in the 2007 consensus, revised in 2021, and in systematic reviews published in 2019 and 2020.5,7,8,10 Each participant had to choose the best corresponding term in the Portuguese language, commonly used for describing the structure in question or suggest another appropriate term, in addition to those that were discriminated in each list.

After analyzing the answers and results of the first step, forms were created listing most voted or suggested terms for each structure, only for the terms with agreement inferior to 70%.

In the third step of the process, two meetings were held with the virtual presence of the participants to analyze the terms which hadn’t reached 70% in the second step, with the purpose of obtaining a definitive consensus on the term in question. The first meeting was held with the presence of 100% of the specialists and the results of the terms for normal skin and melanocytic lesions were analyzed. The second meeting was held with the presence of 80% of the specialists and the terms for non-melanocytic lesions were analyzed.

As a result of the consensus, the most voted terms which were considered the most suitable for use in the Portuguese language will be presented here. The terms are listed in Tables 1, 2, 3, 4 and 5, along with the corresponding description of the confocal microscopy findings and correlation with histology, for normal skin, melanocytic and non-melanocytic lesions.11Fig. 1 shows the terms used to describe the different aspects of collagen in the papillary dermis and the number of participants using each of the mentioned terms. Fig. 2 illustrates the main terms considered for the description of melanocytic and non-melanocytic lesions.

Figure 1.

Terms used in RCM to describe different aspects of collagen in the papillary dermis and number of participants using each term

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Figure 2.

RCM images illustrating some key consensus terms. (A) Polymorphic pagetoid cells – round (red arrow) and dendritic (yellow arrows). (B) Ringed pattern – edged papillae (asterisks). (C) Meshwork pattern – non-edged papillae (asterisks) and dendritic cells in the interpapillary spaces (red arrows). (D) Dense nests (asterisks). (E) Tumor islands (asterisks), peritumoral dark cleft (yellow arrow) and dilated linear blood vessels (red arrow). (F) Tumor island (asterisk), peripheral palisading (red arrow) and peritumoral dark cleft (yellow arrow). (G) Polycyclic and polymorphic papillae (asterisks). (H) Cords and bulbous projections (yellow arrows)

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RCM aims to provide instantaneous, real-time, high-resolution in vivo images, allowing the observation of microanatomical structures (cells, nuclei and tissue architecture) of the skin at a resolution close to the one of histopathology. This tool has been widely used in the diagnosis of melanoma and non-melanoma skin tumors. The images obtained by this method are from planes parallel to the skin, similar to dermoscopy and different from conventional histological sections.3,4

In vivo confocal microscopy has some differences when compared to conventional histopathology. The examination is painless and non-invasive, with no tissue damage. RCM provides black-and-white images as opposed to the pink and purple staining seen in hematoxylin-eosin stained histological slides. The skin is not altered by the fixation or staining process, minimizing artifacts or disruption of the original tissue structure. Currently, confocal microscopes provide a unique opportunity for non-invasive examination of the skin without the need for fluorescent markers or tissue dyes. The contrast in confocal images occurs due to natural variations in the refractive index of organelles, and microstructures in different skin layers.2–4

RCM may eventually help to prevent the unnecessary excision of benign lesions, guide biopsy of suspicious pigmented lesions, map pre- and intraoperative tumor margins, and monitor therapeutic response.12 The interpretation of RCM images is a difficult task with a long learning curve. Moreover, the inconsistent use of terms in scientific meetings and the lack of terminology standardization in Brazilian Portuguese probably represent an even greater challenge for beginners in the incorporation and training in this technology for beginners.

Terminology standardization, with the use of non-redundant terms, facilitates uniformity in the preparation of the RCM exam report and communication between experienced professionals in the area. Aiming at improving the consistency of the use of RCM terms through standardized language, the authors carried out a terminology consensus in Brazilian Portuguese with the creation of a concise and unified glossary for normal skin, melanocytic lesions, and non-melanocytic lesions.

This consensus was used as the main research basis for two studies recently published by Navarrete-Dechent et al. at the American Academy of Dermatology, where they performed a systematic review of RCM terminology used in the literature for both melanocytic and non-melanocytic lesions. The authors gathered all RCM terms described in original articles, and identified probable synonyms with similar definitions and histopathological correlation, which were grouped together.7,8 Therefore, redundant terms were unified and the list of terms was reduced by approximately 50%, facilitating the creation of a concise glossary and, consequently, improve learning and clinical application of RCM by dermatologists.

RCM is a technology that has gained prominence in Brazil since 2009, mainly in the cutaneous oncology scenario, when the first exams were performed. From then on, the nomenclature used is the one described in the English language, generating great difficulty both in learning and in the preparation and interpretation of reports.

Brazilian professionals from different states, active and experienced in the field of RCM, gathered to standardize the most frequently used descriptive terms for the evaluation of normal skin, melanocytic lesions, and non-melanocytic lesions. It is believed that the creation of this glossary in Brazilian Portuguese will be very useful as a guide for the description of RCM images and also as a didactic tool for beginners using this technology.

The methodology used in this study included the possibility of evaluating the nomenclature in three steps when agreement did not reach at least 70% of the participants. The terms that required two or more steps to reach the desired consensus were related to questions of semantics, subjectivity regarding their description and/or variations between descriptive and metaphorical terms. The consensus was reached with emphasis on its practical use and how easy it was to understand the meaning of the term in relation to its histopathological correspondence.

This Brazilian consensus represents an opportunity for dermatologists and physicians specializing in cutaneous oncology to become familiar with RCM, in addition to the possibility of disseminating the technique in clinical and research settings.

The authors expect that this consensus can be applied by Brazilian professionals to expand the learning and use of RCM in different scenarios in the medical field, facilitating debates in symposiums, congresses, and scientific meetings and contributing to national and international publications.

None declared.

Juliana Casagrande Tavoloni Braga: Design and planning of the study; drafting and editing of the manuscript; collection, analysis, and interpretation of data; critical review of the literature; approval of the final version of the manuscript.

Carlos B. Barcaui: Effective participation in research orientation; collection of data; critical review of important intellectual content; approval of the final version of the manuscript.

Ana Maria Pinheiro: Collection of data; critical review of important intellectual content; approval of the final version of the manuscript.

Ana Maria Fagundes Sortino: Collection of data; critical review of important intellectual content; approval of the final version of the manuscript.

Cristina Martinez Zugaib Abdalla: Collection of data; critical review of important intellectual content; approval of the final version of the manuscript.

Gabriella Campos-do-Carmo: Collection of data; critical review of important intellectual content; approval of the final version of the manuscript.

Gisele Gargantini Rezze: Collection of data; critical review of important intellectual content; approval of the final version of the manuscript.

Juan Piñeiro-Maceira: Collection of data; critical review of important intellectual content; approval of the final version of the manuscript.

Lilian Licarião Rocha: Collection of data; critical review of important intellectual content; approval of the final version of the manuscript.

Marcus Maia: Collection of data; critical review of important intellectual content; approval of the final version of the manuscript.

Bianca Costa Soares de Sá: Design and planning of the study; data survey; analysis and interpretation of data; drafting and editing of the manuscript; critical review of the literature; approval of the final version of the manuscript.

None declared.