Basics of Confocal Microscopy and the Complexity of Diagnosing Skin Tumors

Clinical Approaches for the Management of Skin Cancer: A Review of Current Progress in Diagnosis, Treatment, and Prognosis for Patients with Melanoma

Melanoma represents a significant public health challenge due to its increasing incidence and potential for metastasis. This review will explore the current clinical approaches to the management of melanoma, focusing on advancements in diagnosis, treatment, and prognosis. Methods for early detection and accurate staging have been enhanced by new diagnostic strategies. Treatment modalities have expanded beyond traditional surgical excision to include targeted therapy and immunotherapy. Prognostic assessment has benefited from the development of novel biomarkers and genetic profiling. This review will highlight the progress made in the multidisciplinary management of melanoma, underscoring the importance of continuous research to improve patient outcomes.

In Vivo Reflectance Confocal Microscopy Applied to Acral Melanocytic Lesions: A Systematic Review of the Literature

Background: Acral melanocytic lesions often pose a diagnostic and therapeutic challenge for many clinicians. Reflectance confocal microscopy (RCM) is an imaging technique widely used for the assessment of skin cancers. The aim of this review is to explore the applicability of RCM for the diagnosis of nevi and melanoma on the acral sites. Methods: Study selection was conducted based on the application of RCM for acral melanocytic lesions. All types of articles (original articles, short reports, and single case reports) were included in the analysis following PRISMA updated guidelines. Results: The search retrieved 18 papers according to the selection criteria; after removing duplicate records and additional articles by one or more of the exclusion criteria, a total of seven studies were carefully evaluated. Conclusions: RCM seems a valuable and useful additional tool for the diagnosis of acral melanocytic lesions, and its use may decrease the need for invasive procedures to some extent. Visualization of deeper layers may be achieved through mechanical removal of the superficial stratum corneum.

Biomarkers in Cutaneous Keratinocyte Carcinomas

Skin cancer is the most common cancer type in the USA, with over five million annually treated cases and one in five Americans predicted to develop the disease by the age of 70. Skin cancer can be classified as melanoma or non-melanoma (NMSC), the latter including basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (SCC). Development of BCC and SCC is impacted by environmental, behavioral, and genetic risk factors and the incidence is on the rise, with the associated number of deaths surpassing those caused by melanoma, according to recent reports. Substantial morbidity is related to both BCC and SCC, including disfigurement, loss of function, and chronic pain, driving high treatment costs, and representing a heavy financial burden to patients and healthcare systems worldwide. Clinical presentations of BCC and SCC can be diverse, sometimes carrying considerable phenotypic similarities to benign lesions, and underscoring the need for the development of disease-specific biomarkers. Skin biomarker profiling plays an important role in deeper disease understanding, as well as in guiding clinical diagnosis and patient management, prompting the use of both invasive and non-invasive tools to evaluate specific biomarkers. In this work, we review the known and emerging biomarkers of BCC and SCC, with a focus on molecular and histologic biomarkers relevant for aspects of patient management, including prevention/risk assessments, tumor diagnosis, and therapy selection.

Vertical Ex Vivo Dermoscopy in Assessment of Malignant Skin Lesions

The role of vertical ex vivo dermoscopy relevant to clinical diagnosis has not been investigated yet. Study objectives were defining, describing, and determining the importance of the structures visible using vertical ex vivo dermoscopy in the diagnosis of malignant skin lesions, as well as determining their accuracy in the assessment of tumor margins. A prospective, descriptive study was conducted in two University centers. Digital images of completely excised skin lesions, fixed in formalin, before histopathological diagnosis were used for analysis. BCCs had the most diverse dermoscopic presentation on the vertical section, while SCCs showed a similar presentation in most cases. Vertical dermoscopy of thin melanomas was almost identical, unlike nodular melanomas. Thickness accuracy assessed by dermatologist was 0.753 for BCC, 0.810 for SCC, and 0.800 for melanomas, whereas assessment by pathologist was 0.654, 0.752, and 0.833, respectively. The accuracy of tumor width assessment was 0.819 for BCCs, 0.867 for SCCs and 1.000 for melanoma as estimated by a Dermatologist. Interobserver agreement was 0.71 for BCC, 0.799 for SCC and 0.832 for melanomas. Vertical ex vivo dermoscopy may contribute to the distinction between BCCs, SCCs, and melanomas. Moreover, regardless of the doctor's specialty, it enables a good assessment of the tumor's margins.

Comment on '"Poroma-like" branched vessels with rounded endings in dermoscopy of basal cell carcinoma: a new unusual structure'

This article advocates for the use of multiple noninvasive diagnostic tools for assessment and mutual validation to improve diagnostic accuracy in BCC. Different imaging techniques, each with its advantages, can provide multimodal preoperative information for management options that aim to meet the needs of clinicians.

Diagnostic Accuracy of Digital Staining ex vivo Confocal Microscopy for Diagnosing and Subtyping Basal Cell Carcinoma in Fresh Pretherapeutic Punch Biopsies: A Monocentric Prospective Study

BACKGROUND

Ex vivo confocal microscopy using fusion mode and digital staining (EVCM) scans unfixed fresh tissue and produces rapidly digitally stained images of very similar quality to classical pathology. We investigated whether EVCM could represent an alternative to the standard histological examination of the pretherapeutic basal cell carcinoma (BCC) punch biopsies.

OBJECTIVES

The objective of the study was to assess diagnostic accuracy of EVCM versus traditional histopathological examination for diagnosing and subtyping clinically suspicious lesions of BCC in 3-mm fresh and nonfixed punch biopsies.

METHODS

In this prospective monocentric observational study, patients with clinically suspected BCC were consecutively enrolled. Punch biopsies were imaged using EVCM and subsequently processed for standard histologic examination (gold standard). EVCM images were examined by a dermatopathologist blinded to clinical aspect of the lesion and histopathological results. Concordance between the EVCM and histology analysis was calculated with Cohen's kappa (κ) statistic.

RESULTS

Sixty-six patients were recruited, and 106 biopsies were analyzed. EVCM correctly diagnosed 70/73 BCCs and 31/33 non-BCC lesions, corresponding to a sensitivity of 96% and a specificity of 94% (positive predictive value = 97%, negative predictive value = 91%). The EVCM assessment led to over-staging and under-staging of BCC subtypes in 5% and 11% of cases, respectively. It led to over-staging and under-staging of BCC depths in 5% and 15%, respectively. The kappa coefficient for concordance was 0.78 (95% confidence interval [CI]: 0.69-0.88) when considering BCC subtypes and 0.81 (95% CI: 0.72-0.90) when considering BCC depths.

CONCLUSIONS

These results render EVCM as a promising option for "real-time" pretreatment evaluation of clinically suspected BCC lesions. Further larger randomized studies are needed to assess the efficiency of EVCM versus standard care in patients with clinically suspected BCC.

Line-Field Confocal Optical Coherence Tomography: A New Tool for the Differentiation between Nevi and Melanomas?

Until now, the clinical differentiation between a nevus and a melanoma is still challenging in some cases. Line-field confocal optical coherence tomography (LC-OCT) is a new tool with the aim to change that. The aim of the study was to evaluate LC-OCT for the discrimination between nevi and melanomas. A total of 84 melanocytic lesions were examined with LC-OCT and 36 were also imaged with RCM. The observers recorded the diagnoses, and the presence or absence of the 18 most common imaging parameters for melanocytic lesions, nevi, and melanomas in the LC-OCT images. Their confidence in diagnosis and the image quality of LC-OCT and RCM were evaluated. The most useful criteria, the sensitivity and specificity of LC-OCT vs. RCM vs. histology, to differentiate a (dysplastic) nevus from a melanoma were analyzed. Good image quality correlated with better diagnostic performance (Spearman correlation: 0.4). LC-OCT had a 93% sensitivity and 100% specificity compared to RCM (93% sensitivity, 95% specificity) for diagnosing a melanoma (vs. all types of nevi). No difference in performance between RCM and LC-OCT was observed (McNemar's p value = 1). Both devices falsely diagnosed dysplastic nevi as non-dysplastic (43% sensitivity for dysplastic nevus diagnosis). The most significant criteria for diagnosing a melanoma with LC-OCT were irregular honeycombed patterns (92% occurrence rate; 31.7 odds ratio (OR)), the presence of pagetoid spread (89% occurrence rate; 23.6 OR) and the absence of dermal nests (23% occurrence rate, 0.02 OR). In conclusion LC-OCT is useful for the discrimination between melanomas and nevi.

[Confocal line-field OCT]

Optical coherence tomography (OCT) and confocal laser microscopy (CLSM) are established non-invasive methods in clinical dermatological routine diagnosis. Whereas CLSM is especially useful to distinguish between nevi and melanoma, OCT is suitable for the diagnosis and differentiation of non-melanoma skin cancer. Line-field confocal optical coherence tomography (LC-OCT) is a new innovative device, which has better cellular resolution than OCT and a higher penetration depth than CLSM. Similar to CLSM, LC-OCT also allows 3D images in real time to be taken. Therefore LC-OCT is very useful for the examination of skin lesions of all kinds, since it unites the features of CLSM and OCT.

Line-field confocal optical coherence tomography-Practical applications in dermatology and comparison with established imaging methods

BACKGROUND

Non-invasive diagnostic techniques in dermatology gained increasing popularity in the last decade. Reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) are meanwhile established in research and clinical routine. While OCT is mainly indicated for detecting non-melanoma skin cancer, RCM has proven its usefulness additionally in distinguishing melanocytic lesions. Line-field confocal optical coherence tomography (LC-OCT) is an emerging tool combining the principles of both above-mentioned methods.

METHODS

Healthy skin at different body sites and exemplary skin lesions (basal cell carcinoma, malignant melanoma, actinic keratosis) were examined using dermoscopy, RCM, OCT and LC-OCT. Standard features for RCM and OCT and comparable features for LC-OCT were analysed.

RESULTS

LC-OCT has a lower penetration depth but superior resolution compared to OCT. In comparison with RCM, which provides only horizontal sections, LC-OCT creates both vertical and horizontal images in real time and has nearly the same cellular resolution.

DISCUSSION

Our preliminary experiences suggest that LC-OCT combines the advantages of RCM and OCT, with optimal resolution and penetration depth to diagnose all types of skin cancer. Larger systematic studies are needed to further characterize the field of use of this device and its sensitivity and specificity compared to histology.

A Review of Noninvasive Techniques for Skin Cancer Detection in Dermatology

As a result of increasing melanoma incidence and challenges with clinical and histopathologic evaluation of pigmented lesions, noninvasive techniques to assist in the assessment of skin lesions are highly sought after. This review discusses the methods, benefits, and limitations of adhesive patch biopsy, electrical impedance spectroscopy (EIS), multispectral imaging, high-frequency ultrasonography (HFUS), optical coherence tomography (OCT), and reflectance confocal microscopy (RCM) in the detection of skin cancer. Adhesive patch biopsy provides improved sensitivity and specificity for the detection of melanoma without a trade-off of higher sensitivity for lower specificity seen in other diagnostic tools to aid in skin cancer detection, including EIS and multispectral imaging. EIS and multispectral imaging provide objective information based on computer-assisted diagnosis to assist in the decision to biopsy and/or excise an atypical melanocytic lesion. HFUS may be useful for the determination of skin tumor depth and identification of surgical borders, although further studies are necessary to determine its accuracy in the detection of skin cancer. OCT and RCM provide enhanced resolution of skin tissue and have been applied for improved accuracy in skin cancer diagnosis, as well as monitoring the response of nonsurgical treatments of skin cancers and the determination of tumor margins and recurrences. These novel approaches to skin cancer assessment offer opportunities to dermatologists, but are dependent on the individual dermatologist's comfort, knowledge, and desire to invest in training and implementation of noninvasive techniques. These noninvasive modalities may have a role in the complementary assessment of skin cancers, although histopathologic diagnosis remains the gold standard for the evaluation of skin cancer.

Reflectance Confocal Microscopy Can Help the Dermatopathologist in the Diagnosis of Challenging Skin Lesions

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.

Reflectance confocal microscopy made easy: The 4 must-know key features for the diagnosis of melanoma and nonmelanoma skin cancers

BACKGROUND

Reflectance confocal microscopy (RCM)-based skin cancer diagnosis requires proficiency.

OBJECTIVE

To identify a short list of key RCM features of skin cancers and test their diagnostic utility.

METHODS

We identified key RCM features through consensus among 6 experts using a modified Delphi method. To test the diagnostic utility of these RCM key features, 10 novice RCM readers evaluated a subset of 100 RCM cases from a retrospective data set of benign and malignant skin neoplasms.

RESULTS

From 56 features reported in the literature, the experts identified 18 RCM features as highly valuable for skin cancer diagnosis. On the basis of consensus definitions, these RCM features were further clustered into 2 melanoma-specific key features (atypical cells and dermoepidermal junction disarray), 1 basal cell carcinoma-specific key feature (basaloid cords/islands), and 1 squamous cell carcinoma-specific key feature (keratinocyte disarray). The novice reading study showed that the presence of at least 1 of the 4 key features was associated with an overall sensitivity for skin cancer diagnosis of 91%, with a sensitivity for melanoma of 93%, a sensitivity for basal cell carcinoma of 92%, and a sensitivity for squamous cell carcinoma of 67%, and an overall specificity of 57%.

LIMITATIONS

The consensus was based on only six RCM experts and the validation study was retrospective.

CONCLUSIONS

A consensus terminology short list identifying the 4 RCM key features for skin cancer diagnosis may facilitate dissemination of RCM to novice users.

A Retrospective Study of the Diagnostic Accuracy of In Vivo Reflectance Confocal Microscopy for Basal Cell Carcinoma Diagnosis and Subtyping

Current national and European guidelines recommend distinct management approaches for basal cell carcinoma (BCC) based on tumor location, size, and histopathological subtype. In vivo reflectance confocal microscopy (RCM) is a non-invasive skin imaging technique which may change the diagnostic pathway for BCC patients. This study aimed to determine the sensitivity and specificity of RCM for BCC diagnosis, assess the predictive values of several confocal criteria in correctly classifying BCC subtypes, and evaluate the intraobserver reliability of RCM diagnosis for BCC. We conducted a retrospective study in two tertiary care centers in Bucharest, Romania. We included adults with clinically and dermoscopic suspect BCCs who underwent RCM and histopathological examination of excision specimens. For RCM examinations, we used the VivaScope 1500 and histopathology of the surgical excision specimen was the reference standard. Of the 123 cases included in the analysis, BCC was confirmed in 104 and excluded in 19 cases. RCM showed both high sensitivity (97.1%, 95% CI (91.80, 99.40)) and specificity (78.95%, 95% CI (54.43, 93.95)) for detecting BCC. Several RCM criteria were highly predictive for BCC subtypes: cords connected to the epidermis for superficial BCC, big tumor islands, peritumoral collagen bundles and increased vascularization for nodular BCC, and hyporefractile silhouettes for aggressive BCC. Excellent intraobserver agreement (κ = 0.909, p < 0.001) was observed. This data suggests that RCM could be used for preoperative diagnosis and BCC subtype classification in patients with suspected BCCs seen in tertiary care centers.

Advances in the use of reflectance confocal microscopy in melanoma

In vivo reflectance confocal microscopy (RCM) is a noninvasive high-resolution skin imaging tool that has become an important adjunct to clinical exam, dermoscopy and histopathology assessment, in the diagnosis and management of melanoma. RCM generates a horizontal view of the skin, whereby cellular and subcellular (e.g., nuclei, melanophages, collagen) structures, to the level of the upper dermis, are projected onto a screen at near-histological resolution. Morphologic descriptors, standardized terminology, and diagnostic algorithms are well established for the RCM assessment of melanoma, melanocytic, and nonmelanocytic lesions. Clinical applications of RCM in melanoma are broad and include diagnosis, assessment of large lesions on cosmetically sensitive areas, directing areas to biopsy, delineating margins prior to surgery, detecting response to treatment and assessing recurrence. This review will provide an overview of RCM technology, findings by melanoma subtype, clinical applications, as well as explore the accuracy of RCM for melanoma diagnosis, pitfalls and emerging uses of this technology ex vivo.

Interrater and intrarater agreement of confocal microscopy imaging in diagnosing and subtyping basal cell carcinoma

BACKGROUND

Reflectance confocal microscopy (RCM) imaging can be used to diagnose and subtype basal cell carcinoma (BCC) but relies on individual morphologic pattern recognition that might vary among users.

OBJECTIVES

We assessed the inter-rater and intrarater agreement of RCM in correctly diagnosing and subtyping BCC.

METHODS

In this prospective study, we evaluated the inter-rater and intrarater agreement of RCM on BCC presence and subtype among three raters with varying experience who independently assessed static images of 48 RCM cases twice with four-week interval (T1 and T2). Histopathologic confirmation of presence and subtype of BCC from surgical excision specimen was defined as the reference standard.

RESULTS

The inter-rater agreement of RCM for BCC presence showed an agreement of 82% at T1 and 84% at T2. The agreements for subtyping BCC were lower (52% for T1 and 47% for T2). The intrarater agreement of RCM for BCC presence showed an observed agreement that varied from 79% to 92%. The observed agreements for subtyping varied from 56% to 71%.

CONCLUSIONS

In conclusion, our results show that RCM is reliable in correctly diagnosing BCC based on the assessment of static RCM images. RCM could potentially play an important role in BCC management if accurate subtyping will be achieved. Therefore, future clinical studies on reliability and specific RCM features for BCC subtypes are required.

Updates on the Management of Non-Melanoma Skin Cancer (NMSC)

Non-melanoma skin cancers (NMSCs) are the most common malignancy worldwide, of which 99% are basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) of skin. NMSCs are generally considered a curable diseases, yet they currently pose an increasing global healthcare problem due to rising incidence. This has led to a shift in emphasis on prevention of NMSCs with development of various skin cancer prevention programs worldwide. This article aims to summarize the most recent changes and advances made in NMSC management with a focus on prevention, screening, diagnosis, and staging.

Diagnostic accuracy of confocal microscopy imaging vs. punch biopsy for diagnosing and subtyping basal cell carcinoma

Background

In vivo reflectance confocal microscopy (RCM) is a promising non‐invasive skin imaging technique that could facilitate early diagnosis of basal cell carcinoma (BCC) instead of routine punch biopsies. However, the clinical value and utility of RCM vs. a punch biopsy in diagnosing and subtyping BCC is unknown.

Objective

To assess diagnostic accuracy of RCM vs. punch biopsy for diagnosing and subtyping clinically suspected primary BCC.

Methods

A prospective, consecutive cohort of 100 patients with clinically suspected BCC were included at two tertiary hospitals in Amsterdam, the Netherlands, between 3 February 2015 and 2 October 2015. Patients were randomized between two test‐treatment pathways: diagnosing and subtyping using RCM imaging followed by direct surgical excision (RCM one‐stop‐shop) or planned excision based upon the histological diagnosis and subtype of punch biopsy (standard care). The primary outcome was the agreement between the index tests (RCM vs. punch biopsy) and reference standard (excision specimen) in correctly diagnosing BCC. The secondary outcome was the agreement between the index tests and reference standard in correctly identifying the most aggressive BCC subtypes.

Results

Sensitivity to detect BCC was similar for RCM and punch biopsy (100% vs. 93.94%), but a punch biopsy was more specific than RCM (79% vs. 38%). RCM expert evaluation for diagnosing BCC had a sensitivity of 100% and a specificity of 75%. The agreement between RCM and excision specimen in identifying the most aggressive BCC subtype ranged from 50% to 85% vs. 77% by a punch biopsy.

Conclusion

Reflectance confocal microscopy and punch biopsy have comparable diagnostic accuracy to diagnose and subtype BCC depending on RCM experience. Although experienced RCM users could accurately diagnose BCC at a distance, we found an important difference in subtyping BCC. Future RCM studies need to focus on diagnostic accuracy, reliability and specific criteria to improve BCC subtype differentiation.

High-Frequency Ultrasound Examination in the Diagnosis of Skin Cancer

Ultrasound above 14 MHz images epidermis, dermis, and subcutaneous tissues in real time. Tumor depth is ascertained with B-mode. Three-dimensional imaging depicts nonpalpable, in-transit, and satellite lesions. Doppler blood flow technologies measure tumor neovascularity and map vascular structures. Three-dimensional Doppler histogram reconstruction measures tumor aggression and metastatic potential proportional to the percentage of malignant vessels. Subcutaneous investigation reveals nonpalpable metastatic disease and nodal basin lymphadenopathy. Adjacent nerves may be studied. Preservation of the fat-fascia border refines surgical staging of deeper malignancies. Image-guided biopsy is facilitated. Treatment under image guidance is optimized with radiation and various photo and thermal technologies.

One-stop-shop with confocal microscopy imaging vs. standard care for surgical treatment of basal cell carcinoma: an open-label, noninferiority, randomized controlled multicentre trial

BACKGROUND

Routine punch biopsies are considered to be standard care for diagnosing and subtyping basal cell carcinoma (BCC) when clinically suspected.

OBJECTIVES

We assessed the efficacy of a one-stop-shop concept using in vivo reflectance confocal microscopy (RCM) imaging as a diagnostic tool vs. standard care for surgical treatment in patients with clinically suspected BCC.

METHODS

In this open-label, parallel-group, noninferiority, randomized controlled multicentre trial we enrolled patients with clinically suspected BCC at two tertiary referral centres in Amsterdam, the Netherlands. Patients were randomly assigned to the RCM one-stop-shop (diagnosing and subtyping using RCM followed by direct surgical excision) or standard care (planned excision based on the histological diagnosis and subtype of a punch biopsy). The primary outcome was the proportion of patients with tumour-free margins after surgical excision of BCC.

RESULTS

Of the 95 patients included, 73 (77%) had a BCC histologically confirmed using a surgical excision specimen. All patients (40 of 40, 100%) in the one-stop-shop group had tumour-free margins. In the standard-care group tumour-free margins were found in all but two patients (31 of 33, 94%). The difference in the proportion of patients with tumour-free margins after BCC excision between the one-stop-shop group and the standard-care group was -0·06 (90% confidence interval -0·17-0·01), establishing noninferiority.

CONCLUSIONS

The proposed new treatment strategy seems suitable in facilitating early diagnosis and direct treatment for patients with BCC, depending on factors such as availability of RCM, size and site of the lesion, patient preference and whether direct surgical excision is feasible.