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Reflectance confocal microscopy (RCM) is a noninvasive imaging tool that has the potential to revolutionize dermatology. Extensive research in this area in conjunction with the recent assignment of reimbursement codes has made the clinical use of this technology a practical reality. Though there is awareness and use of this technology at large academic centers, a knowledge gap still remains in interpreting RCM images among the dermatology community. We review the key RCM features of melanocytic and nonmelanocytic lesions to provide guidance in distinguishing benign entities from malignant dermatologic neoplasms.

There are multiple, genetically distinct pathways that give rise to melanoma. Melanomas on sun-damaged skin (MSDS), including lentigo maligna and desmoplastic melanoma, have distinct genetic profiles and are uniquely linked to chronic ultraviolet exposure. In this article, we discuss the etiologies of lentigo maligna and desmoplastic melanoma, emerging diagnostic adjuncts that might be helpful for accurately identifying these lesions, and the clinical relevance of their frequent co-occurrence. We present unique and overlapping features of these entities and discuss challenges in MSDS management, including margin assessment, excision, and the potential role of nonsurgical therapy. Last, we address the role of immunotherapy in invasive disease. Understanding MSDS as distinct from melanoma arising on intermittently sun-exposed or sun-protected skin will ultimately help optimize patient outcomes.

Although histopathology is the time-honored gold standard diagnostic measure in dermatology, several factors may detract from an accurate microscopic diagnosis. Limiting factors include: human error, suboptimal biopsy-site selection or biopsy technique, and inherent restrictions of vertical tissue sectioning that lead to incomplete microscopic evaluation of the lesion. Reflectance confocal microscopy (RCM) is a non-invasive imaging tool that allows for the cellular-level examination of the lesion, at a horizontal plane, which may complement the subsequent vertical histopathological tissue examination. Herein, we report a case series whereby prebiopsy RCM examination enhanced the accuracy of histopathological diagnosis or allowed for a critical appraisal of initial histopathological misdiagnosis.

Melanoma in situ and dysplastic nevi with severe atypia present overlapping histopathologic features. Reflectance confocal microscopy findings can be integrated with the dermatopathology report to improve differentiation between melanoma and dysplastic nevi with severe atypia.To compare prevalence of reflectance confocal microscopy findings between melanoma in situ and dysplastic nevi with severe atypia.This retrospective observational study compared reflectance confocal microscopy findings in dermatopathologically diagnosed dysplastic nevi with severe atypia and melanoma in situ, collected between 2007 and 2017 at a private pigmented-lesion clinic. Concordant pathologic diagnosis was defined as unanimous agreement between 3 dermatopathologists who independently reviewed all cases; all other cases were classified as discordant.The study included 112 lesions, 62 concordant melanomas in situ, 28 concordant dysplastic nevi with severe atypia, and 22 discordant lesions. In comparing reflectance confocal microscopy findings in concordant cases, melanoma in situ showed more frequently than dysplastic nevi with severe atypia the presence of epidermal atypical melanocytes as round cells (19/62 vs 0/28; P .001) and dendritic cells (50/62 vs 6/28; P .001), as well as a diffuse distribution of epidermal atypical melanocytes (50/54 vs 3/6; P = .002). In contrast, dysplastic nevi with severe atypia showed the presence of dense melanocytic nests more frequently than melanoma in situ did (15/28 vs 14/62; P = .003).The study was based on a limited number of lesions originating from a single clinic.Reflectance confocal microscopy findings may help differentiate a subset of dysplastic nevi with severe atypia from melanoma in situ.

Background There is lack of uniformity in reflectance confocal microscopy (RCM) terminology for nonmelanocytic lesions (NMLs). Objective To review published RCM terms for NMLs and identify likely synonymous terms. Methods We conducted a systematic review of original research articles published up to August 19, 2017, adhering to Preferred Reporting Items for Systemic Reviews and Meta-Analyses guidelines. Two investigators gathered all published RCM terms used to describe basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and seborrheic keratosis/solar lentigo/lichen planus–like keratosis (SK/SL/LPLK). Synonymous terms were grouped on the basis of similarity in definition and histopathologic correlates. Results The inclusion criteria was met by 31 studies. Average frequency of use per term was 1.6 (range 1-8). By grouping synonymous terms, the number of terms could be reduced from 58 to 18 for BCC, 58 to 36 for SCC, 23 to 12 for SK/SL/LPLK, and from 139 to 66 terms (52.5% reduction) in total. The frequency of term usage stratified by anatomic layer (suprabasal epidermis vs epidermal basal layer, dermoepidermal junction, and superficial dermis) was 27 (25.7%) versus 78 (74.2%) for BCC; 60 (64.5%) versus 33 (34.5%) for SCC, and 15 (45.4%) versus 18 (54.5%) for SK/SL/LPLK, respectively. Limitations Articles that were not peer reviewed were excluded. Conclusion Systematic review of published RCM terms provides the basis for future NMLs terminology consensus.

Lichen planus-like keratosis (LPLK) is an involuting cutaneous lesion often presenting between the fifth and seventh decades of life. These lesions typically appear abruptly as a solitary macule, papule, or plaque that continuously evolves as it undergoes regression. Clinical and dermoscopic features of LPLK can mimic both benign and malignant lesions, often prompting biopsy for accurate diagnosis. We describe a case of LPLK developing in a patient with a history of multiple skin cancers, including melanoma. Dermoscopy revealed peripheral granules and a central area with pinkish-brown pigmentation and a disorganized pattern with shiny white structures and rosettes. Handheld reflectance confocal microscopy (RCM) showed a typical honeycomb pattern with millia-like cysts and comedo-like openings, and lacked pagetoid and dendritic cells. Based on the benign features seen with RCM, the lesion was followed until complete regression was observed. In conclusion, we describe a case of LPLK with clinically and dermoscopically indeterminate features that was successfully monitored with RCM. We intend to highlight the utility of RCM as a diagnostic aid in equivocal lesions in order to prevent unnecessary excisional procedures.

Purpose of Review Reflectance confocal microscopy (RCM) enables imaging of skin lesions at cellular level resolution at the bedside (in vivo) or in freshly excised tissue (ex vivo). This article provides an overview of strengths and limitations of non-invasive RCM in skin cancer diagnosis. Recent Findings RCM features of common melanocytic and non-melanocytic skin neoplasms such as melanoma, actinic keratosis/squamous cell carcinoma, basal cell carcinoma, and nevi have been well defined and show good correlation with dermoscopic and histopathologic findings. Due to its technical properties, RCM is especially suitable for the examination of flat skin lesions. Summary In vivo RCM has been shown to increase the accuracy of non-invasive diagnosis of common skin neoplasms and is a valuable adjunct to dermoscopy, particularly in cosmetically and functionally sensitive areas such as the face or the genital area.

Reflectance confocal microscopy (RCM) is a technology utilized for bedside diagnosis of cutaneous pathology by non-invasive, in vivo, cellular-level imaging. With the recent establishment of reimbursement codes by the US Centers for Medicaid and Medicare Services, RCM is now likely to be employed by clinical dermatologists and impact decision making on skin cancer management. Dermatopathologists, therefore, would benefit from learning how to interpret RCM images and how RCM findings correlate with histopathological criteria of diagnosis. This review briefly explains the principles behind RCM image acquisition, describes the key RCM features of normal skin, and delineates the RCM characteristics of frequently observed benign and malignant neoplasms.

Background: Collision lesions as two independent and unrelated skin tumors often manifest an atypical morphology. Objective: To determine the combinations of collision skin lesions (CSLs). Methods: Twenty-one pigmented lesion clinics in nine countries included 77 histopathologically proven CSLs in this retrospective observational study. Results: Seventy-seven CSLs from 75 patients (median age 59.8 years) were analyzed; 24.7% of CSLs were located on the head and neck area, 5.2% on the upper extremities, 48.1% on the trunk, and 11.7% on the lower extremities; 40.3% revealed a melanocytic component (median age 54.7 years), followed by 45.5% with a basal cell carcinoma (BCC) (median age 62.4 years) and 11.7% with a seborrheic keratosis (median age 64.7 years). CSLs with a BCC component were more often found on the head and neck area compared to tumors with a melanocytic component (34.3% versus 16.1%). Lesions with a melanocytic component were more often detected on the trunk compared to lesions with a BCC (64.5% versus 37.1%). Patients with CSLs with epidermal-epidermal cell combination were older than patients with epidermal-dermal cell combination (63 versus 55.2 years), were more often male than female (63% versus 43.3%), more often had the lesion on the head and neck area (32.6% versus 13.3%), and less often on the upper (2.2 % versus 10%) or lower extremities (8.7% versus 16.6%). Conclusions: CSLs consist of a heterogeneous group of lesions of varying cell types. They are associated with advancing age and cumulative UV-exposure. CSLs manifest a complex morphology making it challenging to diagnose correctly.

Distinguishing between benign and malignant neoplasms of the skin is a daily challenge to dermatologists. With the use of a dermatoscope and other imaging devices, the diagnosis is often more precise. The confocal microscope is a device that uses a near-infrared laser to perform noninvasive imaging of the skin. The benefit is that the images immediately provide additional, cellular-level information that can assist in diagnosis. However, lesions may share overlapping characteristics on confocal microscopy, and hence, benign lesions can still display confocal features concerning for a cancerous process, justifying a biopsy. Here, we present a case of an inverted follicular keratosis imitating a squamous cell carcinoma on confocal microscopy.

This paper presents an approach that combines conventional image processing with deep learning by fusing the features from the individual techniques. We hypothesize that the two techniques, with different error profiles, are synergistic. The conventional image processing arm uses three handcrafted biologically inspired image processing modules and one clinical information module. The image processing modules detect lesion features comparable to clinical dermoscopy information—atypical pigment network, color distribution, and blood vessels. The clinical module includes information submitted to the pathologist—patient age, gender, lesion location, size, and patient history. The deep learning arm utilizes knowledge transfer via a ResNet-50 network that is repurposed to predict the probability of melanoma classification. The classification scores of each individual module from both processing arms are then ensembled utilizing logistic regression to predict an overall melanoma probability. Using cross-validated results of melanoma classification measured by area under the receiver operator characteristic curve (AUC), classification accuracy of 0.94 was obtained for the fusion technique. In comparison, the ResNet-50 deep learning based classifier alone yields an AUC of 0.87 and conventional image processing based classifier yields an AUC of 0.90. Further study of fusion of conventional image processing techniques and deep learning is warranted.

The clinical diagnosis of tumors on the curved surfaces of the face, around the eyes, and on the mucosal surfaces can be difficult, while biopsies and excisions can have functional and aesthetic consequences. To avoid unnecessary surgery, clinicians have been aiming to attain accurate noninvasive diagnosis of lesions at these sites. However, acquisition of high-quality images with dermoscopy and with traditional wide-probe reflectance confocal microscopy (WP-RCM) have been hampered with technical difficulties. This article discusses the technical parameters of the handheld reflectance confocal microscope and discusses its advantages and limitations compared with the WP-RCM.

IMPORTANCE: Basal cell carcinoma (BCC) is the most common skin cancer. Dermoscopic imaging has improved diagnostic accuracy; however, diagnosis of nonpigmented BCC remains limited to arborizing vessels, ulceration, and shiny white structures. OBJECTIVE: To assess multiple aggregated yellow-white (MAY) globules as a diagnostic feature for BCC. DESIGN, SETTING, AND PARTICIPANTS: In this retrospective, single-center, case-control study, nonpigmented skin tumors, determined clinically, were identified from a database of lesions consecutively biopsied during a 7-year period (January 1, 2009, to December 31, 2015). A subset of tumors was prospectively diagnosed, and reflectance confocal microscopy, optical coherence tomography, and histopathologic correlation were performed. Data analysis was conducted from July 1 to September 31, 2019. EXPOSURES: Investigators evaluated for the presence or absence of known dermoscopic criteria. MAY globules were defined as aggregated, white-yellow structures visualized in polarized and nonpolarized light. MAIN OUTCOMES AND MEASURES: The primary outcome was the diagnostic accuracy of MAY globules for the diagnosis of BCC. Secondary objectives included the association with BCC location and subtype. Interrater agreement was estimated. RESULTS: A total of 656 nonpigmented lesions from 643 patients (mean [SD] age, 63.1 [14.9] years; 381 [58.1%] male) were included. In all, 194 lesions (29.6%) were located on the head and neck. A total of 291 (44.4%) were BCCs. MAY globules were seen in 61 of 291 BCC cases (21.0%) and in 3 of 365 other diagnoses (0.8%) (P

Importance: Convolutional neural networks (CNNs) achieve expert-level accuracy in the diagnosis of pigmented melanocytic lesions. However, the most common types of skin cancer are nonpigmented and nonmelanocytic, and are more difficult to diagnose. Objective: To compare the accuracy of a CNN-based classifier with that of physicians with different levels of experience. Design, Setting, and Participants: A CNN-based classification model was trained on 7895 dermoscopic and 5829 close-up images of lesions excised at a primary skin cancer clinic between January 1, 2008, and July 13, 2017, for a combined evaluation of both imaging methods. The combined CNN (cCNN) was tested on a set of 2072 unknown cases and compared with results from 95 human raters who were medical personnel, including 62 board-certified dermatologists, with different experience in dermoscopy. Main Outcomes and Measures: The proportions of correct specific diagnoses and the accuracy to differentiate between benign and malignant lesions measured as an area under the receiver operating characteristic curve served as main outcome measures. Results: Among 95 human raters (51.6% female; mean age, 43.4 years; 95% CI, 41.0-45.7 years), the participants were divided into 3 groups (according to years of experience with dermoscopy): beginner raters (10 years). The area under the receiver operating characteristic curve of the trained cCNN was higher than human ratings (0.742; 95% CI, 0.729-0.755 vs 0.695; 95% CI, 0.676-0.713; P

Despite the successful assignment of Current Procedural Terminology codes, there are barriers to incorporating in vivo reflectance confocal microscopy (RCM) into daily practice. Importantly, the dermatopathologist can play a key role in interpreting RCM images and can use these images to correlate with histopathology. Herein, we describe, using a case series, how RCM can be incorporated into the dermatopothalogist's practice. We also summarize the criteria for RCM diagnosis of common neoplasms.

Background Melanoma remains a challenge to diagnose, especially when appearing on the background of chronically sun-damaged skin (CSDS). Our goal was to identify and quantify the reflectance confocal microscopy (RCM) features of melanoma on non-facial CSDS. Methods Included lesions were biopsy-proven melanomas, from anatomic sites other than the face, neck, scalp and acral skin, with histopathologic finding of solar elastosis in the underlying dermis. All included lesions underwent clinical, dermoscopic and RCM imaging, obtained in a standardized fashion, prior to biopsy. All images were retrospectively analyzed by four observers. Results We identified 33 melanomas from 33 patients with 63.6% male patients and overall mean age of 72.8 years. The salient RCM features included an atypical honeycomb or disarranged epidermal pattern (81.8%), pagetoid infiltration of the epidermis by both round and/or dendritic melanocytes (100%), focal proliferation of predominantly dendritic melanocytes as sheets (78.8%), foci with non-edged papillae (84.8%), junctional thickening (60.6%), areas of irregular ring or meshwork pattern (78.8%), and underlying thickened collagen bundles (51.5%). Conclusion Non-facial CSDS melanomas share features similar to other melanoma types including pagetoid cells and non-edged papillae. The focal proliferation of dendritic pagetoid cells in sheets is similar to that seen in facial CSDS melanomas.

Background Melanomas on chronically sun-damaged skin (CSDS) can be difficult to identify and often manifest morphologic features that overlap with benign lesions. Objective We describe and analyze the clinical and dermoscopic characteristics of melanomas on nonfacial CSDS. Methods Melanoma cases on nonfacial CSDS were retrospectively identified from the biopsy specimen logs of 6 melanoma clinics. Clinical and dermoscopic images were combined into 1 database. Demographics, clinical, dermoscopic, and histopathologic information were analyzed. Descriptive frequencies were calculated. Results One hundred eighty-six cases met the inclusion criteria: 142 melanomas in situ (76%) and 39 invasive (21%; mean thickness, 0.49 mm). Lentigo maligna was the most common histopathologic subtype (n = 76; 40.9%). The most frequent dermoscopic structures were granularity (n = 126; 67.7%) and angulated lines (n = 82; 44%). Vascular structures were more frequent in invasive melanomas (56% vs 12% of in situ melanomas). Most manifested 1 of 3 dermoscopic patterns: patchy peripheral pigmented islands, angulated lines, and tan structureless with granularity pattern. Limitations This was a retrospective study, and evaluators were not blinded to the diagnosis. In addition, interobserver concordance and sensitivity and specificity for dermoscopic structures were not evaluated. Conclusion Outlier lesions manifesting dermoscopic structures, such as granularity, angulated lines, or vessels and any of the 3 described dermoscopic patterns should raise suspicion for melanoma.

Background Little is known about the frequency of clinical and dermoscopic patterns of lentigo maligna (LM) in relation to specific anatomic subsites and patients characteristics. Objective We sought to assess the frequency of clinical and dermoscopic features of LM and to correlate them to specific anatomic subsites, and patients' age and gender. Methods This was a retrospective analysis of clinical and dermoscopic images of a series of consecutive, histopathologically diagnosed, facial and extrafacial LM. Results A total of 201 cases from 200 patients (mean age 69.51 ± 12.26 years) including 120 women were collected. Most cases were located on the face (n = 192, 95.5%). In 102 cases, LM presented as clinically solitary facial macule (s/LM), whereas it was associated with multiple surrounding freckles in the remaining cases. s/LM were significantly smaller ( 10 mm; P = .020) and associated with younger age compared with LM associated with multiple surrounding freckles (mean age 67.73 ± 12.68 years vs 71.34 ± 11.59 years, respectively; P = .036). Dermoscopically, gray color irrespective of a specific pattern was the most prevalent finding seen in 178 (88.6%) cases. Limitations This was a retrospective study. Conclusions The knowledge about patient age, patient gender, and site-related clinical features of LM associated with gray color upon dermoscopy may enhance the clinical recognition of LM.

The detection of melanoma can be challenging. Many patients have clinically equivocal lesions in cosmetically sensitive areas or have multiple suspicious lesions. Epidermal genetic information retrieval is a noninvasive diagnostic method involving the application of adhesive tape onto the skin's surface to recover genomic material from the epidermis. This genomic material can then be used in assays to determine gene expression profiles. Studies have shown the potential of this technology to aid clinicians in differentiating between melanomas and nevi. Although this technology is not meant to replace a biopsy, it can help guide the decision whether to biopsy.

Pigmented squamous cell carcinoma in situ (pSCCis) is difficult to diagnose based on clinical and dermoscopic examination. Reflectance confocal microscopy (RCM) allows noninvasive differentiation between malignant and benign pigmented skin lesions. We determined the frequency of key RCM features of pSCCis and correlated the RCM criteria with the corresponding dermoscopic and histopathologic criteria. The study included 28 lesions with biopsy-proven diagnosis of pSCCis derived from 28 patients. Clinical, dermoscopic, and RCM images of these lesions were retrospectively analyzed by 3 independent observers. Assessment for the presence of RCM criteria revealed scale or parakeratosis (20/28; 71%); irregular honeycomb pattern in the spinous-granular layer (28/28; 100%); spindle-shaped cells with dendritic branches infiltrating the epidermis (12/28; 43%); edged papillae (24/28; 86%), and dilated looped blood vessels within the papillae (18/28; 64%). Fifty-three percent of the cases displayed at least 4 RCM criteria and 96% of cases displayed at least 3 RCM criteria. We propose that the diagnosis of pSCCis could be established based on 1 major criterion-irregular honeycomb pattern-and 2 of the following minor criteria-scale or parakeratosis, spindle-shaped cells with dendritic branches infiltrating the epidermis, edged papillae, and dilated looped blood vessels within the papillae.

BACKGROUND: Nonpigmented skin cancer is common, and diagnosis with the unaided eye is error prone. OBJECTIVE: To investigate whether dermatoscopy improves the diagnostic accuracy for nonpigmented (amelanotic) cutaneous neoplasms. METHODS: We collected a sample of 2072 benign and malignant neoplastic lesions and inflammatory conditions and presented close-up images taken with and without dermatoscopy to 95 examiners with different levels of experience. RESULTS: The area under the curve was significantly higher with than without dermatoscopy (0.68 vs 0.64, P < .001). Among 51 possible diagnoses, the correct diagnosis was selected in 33.1% of cases with and 26.4% of cases without dermatoscopy (P < .001). For experts, the frequencies of correct specific diagnoses of a malignant lesion improved from 40.2% without to 51.3% with dermatoscopy. For all malignant neoplasms combined, the frequencies of appropriate management strategies increased from 78.1% without to 82.5% with dermatoscopy. LIMITATIONS: The study deviated from a real-life clinical setting and was potentially affected by verification and selection bias. CONCLUSIONS: Dermatoscopy improves the diagnosis and management of nonpigmented skin cancer and should be used as an adjunct to examination with the unaided eye.

Fuzzy logic image analysis techniques were used to analyze three shades of blue (lavender blue, light blue, and dark blue) in dermoscopic images for melanoma detection. A logistic regression model provided up to 82.7% accuracy for melanoma discrimination for 866 images. With a support vector machines (SVM) classifier, lower accuracy was obtained for individual shades (79.9–80.1%) compared with up to 81.4% accuracy with multiple shades. All fuzzy blue logic alpha cuts scored higher than the crisp case. Fuzzy logic techniques applied to multiple shades of blue can assist in melanoma detection. These vector-based fuzzy logic techniques can be extended to other image analysis problems involving multiple colors or color shades.

Dermoscopy is useful for skin cancer screening, but a detailed approach is required that integrates this tool into a rational clinical work flow. To investigate clinician perceptions and behavior in approaching patients with skin tumors, a survey was launched by electronic mail through the International Dermoscopy Society. After 4 months, the responses were analyzed and significant findings calculated. Considering the current approach of study participants in examining patients for skin cancer, an up-to-date system of triage is presented in this review, which aims to promote an improved diagnostic accuracy and more timely management of skin malignancy.

Background Differentiation between seborrheic keratosis (SK) and skin cancers may be difficult. Reflectance confocal microscopy (RCM) enables noninvasive assessment of skin neoplasms at cellular-level resolution. Objective We sought to describe RCM features of SK and to correlate these RCM findings with dermoscopic structures. Methods Clinical, dermoscopic, and RCM images of 45 consecutive SK were obtained at a private and university dermatology clinic. Fourteen SK were biopsied because of equivocal clinical or dermoscopic features. Results With RCM, all SK displayed a regular honeycomb pattern of the epidermis and densely packed, round to polymorphous, well-circumscribed dermal papillae at the dermoepidermal junction, features suggestive of a benign neoplasm. RCM features indicating the diagnosis of SK were also observed, including epidermal projections (43/45 SK; 96%) and keratin-filled invaginations (36/45 SK; 80%) at the lesion surface; corneal pseudocysts at epidermal layers (19/45 SK; 42%); and melanophages (21/45 SK; 47%) and dilated round and linear blood vessels (21/45 SK; 47%) in the papillary dermis. Of biopsied SK, 93% (13/14) displayed at least 3 characteristic RCM findings in the absence of RCM features suggestive of malignancy. Limitations This was a limited study sample and retrospective study design. Conclusions SK display a distinct set of RCM criteria despite their variable clinical and dermoscopic appearances.

Background: The term ‘collision tumor' refers to the association of 2 or more different neoplasms within the same lesion. The association of a benign neoplasm with a malignant neoplasm is of particular significance and warrants diagnostic accuracy. Objective: The purpose of our study was to see if reflectance confocal microscopy (RCM) was a valuable tool when dealing with collision tumors. Methods: We retrospectively evaluated 24 histologically confirmed cases of collision tumors, which were initially assessed using dermoscopy and RCM. Results: The malignancy most commonly detected in association with collision tumors was basal cell carcinoma (BCC) (n = 13), followed by melanoma (n = 5, of which 2 collided with BCC) and squamous cell carcinoma in situ (n = 4). Seborrheic keratoses were the most common benign neoplasms found in association with collision tumors (n = 18), followed by nevi (n = 7). Dermoscopy revealed the malignant component in 14 out of 20 lesions compared to RCM, which revealed a malignant component in 19 out of 20 neoplasms. There was excellent concordance between RCM and histopathology with regard to the identification of a malignant component within a tumor (kappa value >0.9). Conclusion: The dermatoscope and the reflectance confocal microscope, when used in conjunction, are valuable tools aiding in the diagnosis of collision tumors.

The clinical diagnosis of tumors on the curved surfaces of the face, around the eyes, and on the mucosal surfaces can be difficult, while biopsies and excisions can have functional and aesthetic consequences. To avoid unnecessary surgery, clinicians have been aiming to attain accurate noninvasive diagnosis of lesions at these sites. However, acquisition of high-quality images with dermoscopy and with traditional wide-probe reflectance confocal microscopy (WP-RCM) have been hampered with technical difficulties. This article discusses the technical parameters of the handheld reflectance confocal microscope and discusses its advantages and limitations compared with the WP-RCM.

Efforts have been expended to evaluate the reflectance confocal microscopy (RCM) features of different clinical entities in order to more thoroughly delineate benign versus malignant features. In this way, RCM can help clinicians to be more selective in regard to undertaking appropriate skin biopsies and improving their benign to malignant ratio. Herein, we report a case of a histopathologically proven melanoacanthoma, a variant of seborrheic keratosis. There are scarce reports describing the RCM features of melanoacanthoma. Our case demonstrated RCM features that were suspicious for melanoma. More RCM images of this benign entity are needed to establish definitive diagnostic criteria.

IMPORTANCE: The comparative diagnostic performance of dermoscopic algorithms and their individual criteria are not well studied. OBJECTIVES: To analyze the discriminatory power and reliability of dermoscopic criteria used in melanoma detection and compare the diagnostic accuracy of existing algorithms. DESIGN, SETTING, AND PARTICIPANTS: This was a retrospective, observational study of 477 lesions (119 melanomas [24.9%] and 358 nevi [75.1%]), which were divided into 12 image sets that consisted of 39 or 40 images per set. A link on the International Dermoscopy Society website from January 1, 2011, through December 31, 2011, directed participants to the study website. Data analysis was performed from June 1, 2013, through May 31, 2015. Participants included physicians, residents, and medical students, and there were no specialty-type or experience-level restrictions. Participants were randomly assigned to evaluate 1 of the 12 image sets. MAIN OUTCOMES AND MEASURES: Associations with melanoma and intraclass correlation coefficients (ICCs) were evaluated for the presence of dermoscopic criteria. Diagnostic accuracy measures were estimated for the following algorithms: the ABCD rule, the Menzies method, the 7-point checklist, the 3-point checklist, chaos and clues, and CASH (color, architecture, symmetry, and homogeneity). RESULTS: A total of 240 participants registered, and 103 (42.9%) evaluated all images. The 110 participants (45.8%) who evaluated fewer than 20 lesions were excluded, resulting in data from 130 participants (54.2%), 121 (93.1%) of whom were regular dermoscopy users. Criteria associated with melanoma included marked architectural disorder (odds ratio [OR], 6.6; 95% CI, 5.6-7.8), pattern asymmetry (OR, 4.9; 95% CI, 4.1-5.8), nonorganized pattern (OR, 3.3; 95% CI, 2.9-3.7), border score of 6 (OR, 3.3; 95% CI, 2.5-4.3), and contour asymmetry (OR, 3.2; 95% CI, 2.7-3.7) (P

Reflectance confocal microscopy (RCM) is an FDA approved noninvasive optical imaging technique that acquires cellular level-resolution skin images in vivo. Herein, we report a case of histopathologically proven large cell acanthoma (LCA) whose RCM features simulate those of squamous cell carcinoma in situ.

Basal cell carcinoma (BCC) is the most common type of skin cancer and is usually nonpigmented. Shiny white structures (SWSs) are frequently present in BCC.To determine the diagnostic accuracy of various morphologies of SWSs for diagnosis of nonpigmented BCC.Nonpigmented skin tumors, determined clinically and dermoscopically, were identified from a database of lesions consecutively biopsied over a 3-year period (January 2, 2009, to December 31, 2012) from a single dermatology practice. Data analysis was conducted from October 9, 2014, to November 15, 2015. Investigators blinded to histopathologic diagnosis evaluated the polarized dermoscopic images for the presence of SWSs, which were categorized as blotches, strands, short white lines, and rosettes. Measures of diagnostic accuracy for BCC were estimated. Participants included 2375 patients from a dermatologic clinic in Plantation, Florida. Review of the medical records identified 2891 biopsied skin lesions; 457 of these were nonpigmented neoplasms.Diagnosis of BCC with dermoscopy compared with all other diagnoses combined was the primary outcome; the secondary outcome was diagnosis of BCC compared with amelanotic melanoma. We calculated diagnostic accuracy measured as odds ratios (ORs), sensitivity, and specificity of shiny white blotches and/or strands for the diagnosis of BCC.Of the 457 nonpigmented neoplasms evaluated, 287 (62.8%) were BCCs, 106 (23.2%) were squamous cell carcinoma, 39 (8.5%) were lichen planus-like keratosis, 21 (4.6%) were melanomas, and 4 (0.9%) were nevi. The prevalence of SWSs was 49.0% (n = 224). In multivariate analysis (reported as OR [95% CI]) controlling for age, sex, and anatomical location, the presence of any SWS was associated with a diagnosis of BCC (2.3 [1.5-3.6]; P .001). Blotches (6.3 [3.6-10.9]; P .001), strands (4.9 [2.9-8.4]; P .001), and blotches and strands together (6.1 [3.3-11.3]; P .001) were positively associated with BCC. Shiny white blotches and strands together had a diagnostic sensitivity of 30% and specificity of 91%.The combined presence of shiny white blotches and strands is associated with high diagnostic specificity for nonpigmented BCC.

Importance Reflectance confocal microscopy (RCM), a cellular-level, in vivo imaging technique, may be potentially used for monitoring melanocytic neoplasms for microscopic stability vs changes over time. Objective To test feasibility of using RCM to track specific microscopic structures within nevi over 1 year. Design, Setting, and Participants This was an observational study, a review of prospectively acquired RCM images, performed at a tertiary academic medical center. Seventeen patients were enrolled from adult patients presenting to pigmented lesion clinic; from each participant, 3 confirmed benign nevi were randomly selected from the upper and lower back and from the lower extremity. Exposures Nevi underwent standardized RCM imaging at baseline and after 1 year. Main Outcomes and Measures We tested interobserver reproducibility in recognition of tissue anchors, RCM structures that can be identified at 2 time points. We used 2 tests to measure concordance between independent readers: (1) In the multiple choice matching test (n = 43 nevi), readers were shown a tissue anchor in a baseline RCM image (≤1 × 1-mm field-of-view) and asked to identify the same structure in 1 of 4 equally sized RCM images obtained from the same nevus at follow-up. (2) In the annotation test (n = 29 nevi), readers were shown a tissue anchor in a follow-up RCM image (≤1× 1-mm field-of-view) and asked to annotate the corresponding location of this structure in the baseline RCM mosaic image (≤5 × 5-mm field-of-view) from the same nevus; good agreement was defined as annotations deviant by less than 10% of the mosaic's width. Results In total, 17 patients (mean age, 45 years [range, 28-70 years]; 10 [59%] were women) contributed a total of 51 nevi, of which 44 nevi (86%) were used for the study. Images from 7 nevi (14%) were suboptimal in quality. Tissue anchors were identified at both time points in all 44 nevi. Selected tissue anchors were located at a mean depth of 54.3 µm; the most commonly selected anchors (37 of 44 images [84.1%]) were dermal papillae. In the multiple choice matching test, compared with a reference reader, 2 readers correctly matched baseline to follow-up tissue anchors in 40 of 43 nevi (93%; P

BACKGROUND: Evolving dermoscopic terminology motivated us to initiate a new consensus. OBJECTIVE: We sought to establish a dictionary of standardized terms. METHODS: We reviewed the medical literature, conducted a survey, and convened a discussion among experts. RESULTS: Two competitive terminologies exist, a more metaphoric terminology that includes numerous terms and a descriptive terminology based on 5 basic terms. In a survey among members of the International Society of Dermoscopy (IDS) 23.5% (n = 201) participants preferentially use descriptive terminology, 20.1% (n = 172) use metaphoric terminology, and 484 (56.5%) use both. More participants who had been initially trained by metaphoric terminology prefer using descriptive terminology than vice versa (9.7% vs 2.6%, P < .001). Most new terms that were published since the last consensus conference in 2003 were unknown to the majority of the participants. There was uniform consensus that both terminologies are suitable, that metaphoric terms need definitions, that synonyms should be avoided, and that the creation of new metaphoric terms should be discouraged. The expert panel proposed a dictionary of standardized terms taking account of metaphoric and descriptive terms. LIMITATIONS: A consensus seeks a workable compromise but does not guarantee its implementation. CONCLUSION: The new consensus provides a revised framework of standardized terms to enhance the consistent use of dermoscopic terminology.