Reflectance confocal microscopy and dermoscopy for in vivo, non-invasive skin imaging of superficial basal cell carcinoma

Superficial basal cell carcinoma mimicking Bowen's disease: Diagnosis with noninvasive imaging

BACKGROUND

Superficial basal cell carcinoma (SBCC) is the rare subtype of basal cell carcinoma (BCC). BCC occurs in exposed areas such as the head and face, SCBB prone to form in trunk. Due to the manifestation of erythema and desquamation, it is prone to misdiagnosed as Bowen's disease in clinica.

MATERIALS AND METHODS

A 68-year-old female presented with coin-sized erythema located on the lower abdomen for 5 years. Histopathological examination was performed, and results informed the diagnosis of SBCC. Lesions were detected by dermoscopy, reflectance confocal microscopy (RCM) and multiphoton microscopy (MPM).

RESULTS

Dermoscopy revealed yellow-red background with more dendritic and linear proliferating vessels and more blue-gray nonaggregated dots structures. RCM displayed streaming of stratum spinosum, tortuous dilated vessels, highlighted inflammatory cells, and medium refraction round and oval tumor cell masses. MPM showed epidermal cells in polar arrangement, increased cell spacing, disorganized stratum granulosum and elastic fibers are gathered in clusters.

CONCLUSION

We described a case of SBCC detected by dermoscopy, RCM and MPM. Noninvasive imaging features may provide a potentially tools in recognition and differentiation of SBCC.

Diagnostic aid to subepidermal calcified nodule with dermoscopy and reflectance confocal microscopy: a case report

BACKGROUND

Subepidermal calcified nodule (SCN) is a type of calcinosis cutis that usually occurs in children. The lesions in the SCN resemble those of other skin diseases, such as pilomatrixoma, molluscum contagiosum, and juvenile xanthogranuloma, leading to a high rate of misdiagnoses. Noninvasive in vivo imaging techniques, represented by dermoscopy and reflectance confocal microscopy (RCM), have dramatically accelerated skin cancer research over the past decade, and their applications have greatly expanded into other skin disorders. However, the features of an SCN in dermoscopy and RCM have yet to be reported previously. Combining these novel approaches with conventional histopathological examinations is a promising method for increasing diagnostic accuracy.

CASE PRESENTATION

We report on a case of SCN of the eyelid diagnosed with the aid of dermoscopy and RCM. A 14-year-old male patient who presented with a painless yellowish-white papule on his left upper eyelid was previously diagnosed with a common wart. Unfortunately, treatment with recombinant human interferon gel was not effective. To achieve a correct diagnosis, dermoscopy and RCM were performed. The former showed closely grouped multiple yellowish-white clods surrounded by linear vessels, and the latter exhibited hyperrefractile material nests at the dermal-epidermal junction level. The alternative diagnoses were, therefore, excluded because of in vivo characterizations. Subsequent surgical excision, histological examination, and von Kossa staining were performed. Pathology showed hyperkeratosis of the epidermis, a downward-directed basal-layer expansion, and small amorphous basophilic deposits scattered throughout the papillary dermis. The von Kossa staining confirmed calcium deposits in the lesion. An SCN was then diagnosed. During the 6-month follow-up, no relapse was observed.

CONCLUSIONS

Patients with SCN could benefit from dermoscopy and RCM, which help achieve an accurate diagnosis. Clinicians should consider the possibility of an SCN for an adolescent patient with painless yellowish-white papules.

Skin Cancer Pathobiology at a Glance: A Focus on Imaging Techniques and Their Potential for Improved Diagnosis and Surveillance in Clinical Cohorts

Early diagnosis is essential for completely eradicating skin cancer and maximizing patients' clinical benefits. Emerging optical imaging modalities such as reflectance confocal microscopy (RCM), optical coherence tomography (OCT), magnetic resonance imaging (MRI), near-infrared (NIR) bioimaging, positron emission tomography (PET), and their combinations provide non-invasive imaging data that may help in the early detection of cutaneous tumors and surgical planning. Hence, they seem appropriate for observing dynamic processes such as blood flow, immune cell activation, and tumor energy metabolism, which may be relevant for disease evolution. This review discusses the latest technological and methodological advances in imaging techniques that may be applied for skin cancer detection and monitoring. In the first instance, we will describe the principle and prospective clinical applications of the most commonly used imaging techniques, highlighting the challenges and opportunities of their implementation in the clinical setting. We will also highlight how imaging techniques may complement the molecular and histological approaches in sharpening the non-invasive skin characterization, laying the ground for more personalized approaches in skin cancer patients.

Langerhans Cells-Revising Their Role in Skin Pathologies

Langerhans cells (LCs) constitute a cellular immune network across the epidermis. Because they are located at the skin barrier, they are considered immune sentinels of the skin. These antigen-presenting cells are capable of migrating to skin draining lymph nodes to prime adaptive immune cells, namely T- and B-lymphocytes, which will ultimately lead to a broad range of immune responses. Moreover, LCs have been shown to possess important roles in the anti-cancer immune responses. Indeed, the literature nicely highlights the role of LCs in melanoma. In line with this, LCs have been found in melanoma tissues where they contribute to the local immune response. Moreover, the immunogenic properties of LCs render them attractive targets for designing vaccines to treat melanoma and autoimmune diseases. Overall, future studies will help to enlarge the portfolio of immune properties of LCs, and aid the prognosis and development of novel therapeutic approaches to treating skin pathologies, including cancers.

Molecular markers of recurrence of basal cell skin cancer

Basal cell carcinoma is the most common skin cancer worldwide, with rates increasing by almost 10% annually. It representing a growing public health problem with negative psychosocial and economic consequences. Analysis of gene expression and proteomic profiling of tumor cells and the tumor microenvironment strongly suggests that certain molecules involved in the pathogenetic pathways of skin cancer may represent novel prognostic biomarkers in basal cell skin cancer. The PubMed, MedLine, Web of Science and RSCI databases were used to search for the necessary literature.

Skin Cancer Research Goes Digital: Looking for Biomarkers within the Droplets

Skin cancer, which includes the most frequent malignant non-melanoma carcinomas (basal cell carcinoma, BCC, and squamous cell carcinoma, SCC), along with the difficult to treat cutaneous melanoma (CM), pose important worldwide issues for the health care system. Despite the improved anti-cancer armamentarium and the latest scientific achievements, many skin cancer patients fail to respond to therapies, due to the remarkable heterogeneity of cutaneous tumors, calling for even more sophisticated biomarker discovery and patient monitoring approaches. Droplet digital polymerase chain reaction (ddPCR), a robust method for detecting and quantifying low-abundance nucleic acids, has recently emerged as a powerful technology for skin cancer analysis in tissue and liquid biopsies (LBs). The ddPCR method, being capable of analyzing various biological samples, has proved to be efficient in studying variations in gene sequences, including copy number variations (CNVs) and point mutations, DNA methylation, circulatory miRNome, and transcriptome dynamics. Moreover, ddPCR can be designed as a dynamic platform for individualized cancer detection and monitoring therapy efficacy. Here, we present the latest scientific studies applying ddPCR in dermato-oncology, highlighting the potential of this technology for skin cancer biomarker discovery and validation in the context of personalized medicine. The benefits and challenges associated with ddPCR implementation in the clinical setting, mainly when analyzing LBs, are also discussed.

Nodular and Micronodular Basal Cell Carcinoma Subtypes Are Different Tumors Based on Their Morphological Architecture and Their Interaction with the Surrounding Stroma

Basal cell carcinoma (BCC) is the most frequent cancer of the skin and comprises low-risk and high-risk subtypes. We selected a low-risk subtype, namely, nodular (N), and a high-risk subtype, namely, micronodular (MN), with the aim to identify differences between them using a classical morphometric approach through a gray-level co-occurrence matrix and histogram analysis, as well as an approach based on deep learning semantic segmentation. From whole-slide images, pathologists selected 216 N and 201 MN BCC images. The two groups were then manually segmented and compared based on four morphological areas: center of the BCC islands (tumor, T), peripheral palisading of the BCC islands (touching tumor, TT), peritumoral cleft (PC) and surrounding stroma (S). We found that the TT pattern varied the least, while the PC pattern varied the most between the two subtypes. The combination of two distinct analysis approaches yielded fresh insights into the characterization of BCC, and thus, we were able to describe two different morphological patterns for the T component of the two subtypes.

Matrix Effectors in the Pathogenesis of Keratinocyte-Derived Carcinomas

Basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC), referred to as keratinocyte carcinomas, are skin cancer with the highest incidence. BCCs, rarely metastasize; whereas, though generally not characterized by high lethality, approximately 2–4% of primary cSCCs metastasize with patients exhibiting poor prognosis. The extracellular matrix (ECM) serves as a scaffold that provides structural and biological support to cells in all human tissues. The main components of the ECM, including fibrillar proteins, proteoglycans (PGs), glycosaminoglycans (GAGs), and adhesion proteins such as fibronectin, are secreted by the cells in a tissue-specific manner, critical for the proper function of each organ. The skin compartmentalization to the epidermis and dermis compartments is based on a basement membrane (BM), a highly specialized network of ECM proteins that separate and unify the two compartments. The stiffness and assembly of BM and tensile forces affect tumor progenitors' invasion at the stratified epithelium's stromal border. Likewise, the mechanical properties of the stroma, e.g., stiffness, are directly correlated to the pathogenesis of the keratinocyte carcinomas. Since the ECM is a pool for various growth factors, cytokines, and chemokines, its' intense remodeling in the aberrant cancer tissue milieu affects biological functions, such as angiogenesis, adhesion, proliferation, or cell motility by regulating specific signaling pathways. This review discusses the structural and functional modulations of the keratinocyte carcinoma microenvironment. Furthermore, we debate how ECM remodeling affects the pathogenesis of these skin cancers.

Basal cell carcinoma: Comprehensive clinical and histopathological aspects, novel imaging tools and therapeutic approaches (Review)

Basal cell carcinoma (BCC) is one of the most common malignant tumors worldwide, involving the skin. It is also part of keratinocyte carcinomas, alongside its squamous counterpart. It has low mortality and extremely low metastatic rates (although when present, it indicates a poor patient prognosis); it also has a high morbidity rate through local destruction and recurrence, particularly when perineural invasion is observed, clinically or histopathologically. BCC development is the result of environmental and patient factors, with genetics and ultraviolet radiation playing major roles. The clinical and histopathological aspects vary according to tumor subtype, being classified as high-risk tumors (nodular, superficial, pigmented and infundibulocystic BCC with adnexal differentiation) and fibroepithelial subtypes, or as high-risk tumors (micronodular, infiltrating, sclerosing/morphoeic and basosquamous subtype or the type with sarcomatoid differentiation). Dermoscopy is now complimented by novel in vivo diagnostic tools (optical coherence tomography, reflectance confocal microscopy, high-resolution ultrasonography, Raman spectroscopy or terahertz pulse imaging), improving the diagnostic accuracy and providing tumor depth and lateral margins without the use of invasive techniques. Novel treatment approaches for the treatment of BCC have recently been investigated with the use of hedgehog pathway inhibitors, such as Vismodegib. These approaches aim for complete resolution, minimal side-effects, high patient satisfaction with the optimal cosmetic results, particularly in key areas, such as the face. The present review article summarizes and discusses the comprehensive clinical and histopathological aspects of BCC, and presents novel imaging tools and therapeutic approaches that have been identified.

Seeing through the Skin: Photoacoustic Tomography of Skin Vasculature and Beyond

Skin diseases are the most common human diseases and manifest in distinct structural and functional changes to skin tissue components such as basal cells, vasculature, and pigmentation. Although biopsy is the standard practice for skin disease diagnosis, it is not sufficient to provide in vivo status of the skin and highly depends on the timing of diagnosis. Noninvasive imaging technologies that can provide structural and functional tissue information in real time would be invaluable for skin disease diagnosis and treatment evaluation. Among the modern medical imaging technologies, photoacoustic (PA) tomography (PAT) shows great promise as an emerging optical imaging modality with high spatial resolution, high imaging speed, deep penetration depth, rich contrast, and inherent sensitivity to functional and molecular information. Over the last decade, PAT has undergone an explosion in technical development and biomedical applications. Particularly, PAT has attracted increasing attention in skin disease diagnosis, providing structural, functional, metabolic, molecular, and histological information. In this concise review, we introduce the principles and imaging capability of various PA skin imaging technologies. We highlight the representative applications in the past decade with a focus on imaging skin vasculature and melanoma. We also envision the critical technical developments necessary to further accelerate the translation of PAT technologies to fundamental skin research and clinical impacts.

A Comparative Study of Pigmented and Non-pigmented Basal Cell Carcinoma in Reflectance Confocal Microscopy

BACKGROUND/AIM

Basal cell carcinoma (BCC) is a common skin cancer, especially in the elderly population. The probability of BCC development increases past the age of 55. Dermoscopy and reflectance confocal microscopy (RCM) are two modern tools useful in the diagnosis of BCC.

PATIENTS AND METHODS

This is a retrospective study conducted on a group of 21 patients with a confirmed diagnosis of BCC. All patients were examined by dermoscopy and RCM. Dermoscopic images were taken using a videodermoscope. RCM was performed in three layers: epidermal, dermoepidermal junction (DEJ), and superficial dermal layer. In each layer, a few RCM criteria of basal cell carcinoma diagnosis were taken into consideration.

RESULTS

Dermoscopy of pigmented BCCs revealed blue globules of pigment (p<0.05), gray and blue ovoid nests, which were absent in the entire non-pigmented carcinomas group. In RCM, the epidermis showed no differences between pigmented and non-pigmented carcinomas, however, significant differences were observed at the DEJ. In pigmented BCCs, cordlike structures and plump atypical cells were observed (p<0.05), while in non-pigmented carcinomas, dark silhouettes were present (p<0.05).

CONCLUSION

To our knowledge, that is the first study comparing features between pigmented and non-pigmented BCC by RCM. Pigmented and non-pigmented BCCs presented different features in both dermoscopy and RCM. Furthermore, RCM revealed more discriminating features at the DEJ than dermoscopy, thus can be more efficient in the differential diagnosis of difficult BCC.

Current Perspectives on the Role of Matrix Metalloproteinases in the Pathogenesis of Basal Cell Carcinoma

Basal cell carcinoma (BCC) is the most common skin malignancy, which rarely metastasizes but has a great ability to infiltrate and invade the surrounding tissues. One of the molecular players involved in the metastatic process are matrix metalloproteinases (MMPs). MMPs are enzymes that can degrade various components of the extracellular matrix. In the skin, the expression of MMPs is increased in response to various stimuli, including ultraviolet (UV) radiation, one of the main factors involved in the development of BCC. By modulating various processes that are linked to tumor growth, such as invasion and angiogenesis, MMPs have been associated with UV-related carcinogenesis. The sources of MMPs are multiple, as they can be released by both neoplastic and tumor microenvironment cells. Inhibiting the action of MMPs could be a useful therapeutic option in BCC management. In this review that reunites the latest advances in this domain, we discuss the role of MMPs in the pathogenesis and evolution of BCC, as molecules involved in tumor aggressiveness and risk of recurrence, in order to offer a fresh and updated perspective on this field.

Dermoscopic Findings in the Presurgical Evaluation of Basal Cell Carcinoma. A Prospective Study

BACKGROUND

Surgery is the best treatment for basal cell carcinoma (BCC); however, incomplete excisions are possible.

OBJECTIVE

Assessment of the accurateness of dermoscopy and clinical evaluation in the detection of borders of BCC and description of dermoscopic findings in clinically healthy tissue surrounding BCC.

MATERIALS AND METHODS

Eighty-eight lesions with clinical dermoscopic diagnosis of BCC were examined clinically and dermoscopically, to delineate the correct site of surgical incision, demarcating the respective margins with colred dermographic pencils. Specific dermoscopic features were searched in the skin adjacent to the demarcated clinical margin.

RESULTS

In 29 of 88 lesions, clinical and dermoscopic margins of the tumor coincided. In the remaining 59 (67%), 10 (16.9%) presented, in the lesion area identified under dermoscopy, classical criteria for BCC and 57 (96.6%) nonclassical criteria. Differences between clinical and dermoscopic margins were significantly more frequent in superficial BCCs (p = .006). The frequency was not significantly different (p = .85) in relation to body sites.

CONCLUSION

Dermoscopy improves the identification of margins for surgical excision in BCC. The observation of nontraditional dermoscopic criteria of BCC, mainly pink-white areas and short telangiectasias in the area between clinically and dermoscopically detected margins, helps to define the actual tumoral margins and to achieve a really radical excision.

Peritumoral Clefting and Expression of MMP-2 and MMP-9 in Basal Cell Carcinoma of the Skin

BACKGROUND/AIM

Peritumoral clefting is one of the main histologic features of basal cell carcinoma of the skin (BCC). The aim of the study was to analyze the expression of MMP-2 and MMP-9 both in cells of basal cell carcinoma and in the adjacent stroma and to correlate the findings of immunohistochemical analysis with the presence of peritumoral clefting.

PATIENTS AND METHODS

The study was made on archival material comprising 48 cases of BCC. These were scanned for the presence of peritumoral clefts. The results of immunohistochemical staining for MMP-2 and MMP-9 were determined semiquantitatively using immunohistochemical staining index (ISI).

RESULTS

Peritumoral retractions were found in 40 BCC cases. Positive immunohistochemical reaction for MMP-2 in tumor cells was found in 47 cases and in all cases in the adjacent stroma. Positive immunostaining for MMP-9 in BCC tumor cells was observed in 37 cases and in all cases in the adjacent stroma. There was no statistically significant association between peritumoral retractions and expression of MMPs. A statistically significant correlation was found in the expression of both MMP-2 and MMP-9 between the tumor and the stroma.

CONCLUSION

Tumor cells elaborate MMP-2 and -9, but they also produce some other factors that may induce production of MMPs in adjacent stromal cells. The role of MMPs in the development of peritumoral clefts could not be confirmed.

Recent Advances in Signaling Pathways Comprehension as Carcinogenesis Triggers in Basal Cell Carcinoma

Basal cell carcinoma (BCC) is the most common malignant skin tumor. BCC displays a different behavior compared with other neoplasms, has a slow evolution, and metastasizes very rarely, but sometimes it causes an important local destruction. Chronic ultraviolet exposure along with genetic factors are the most important risk factors involved in BCC development. Mutations in the PTCH1 gene are associated with Gorlin syndrome, an autosomal dominant disorder characterized by the occurrence of multiple BCCs, but are also the most frequent mutations observed in sporadic BCCs. PTCH1 encodes for PTCH1 protein, the most important negative regulator of the Hedgehog (Hh) pathway. There are numerous studies confirming Hh pathway involvement in BCC pathogenesis. Although Hh pathway has been intensively investigated, it remains incompletely elucidated. Recent studies on BCC tumorigenesis have shown that in addition to Hh pathway, there are other signaling pathways involved in BCC development. In this review, we present recent advances in BCC carcinogenesis.

In Vivo Reflectance Confocal Microscopy-Diagnostic Criteria for Actinic Cheilitis and Squamous Cell Carcinoma of the Lip

Actinic cheilitis (AC) is one of the most frequent pathologies to affect the lips. Studies show that the most commonplace oral malignancy, squamous cell carcinoma (SCC), often emerges from AC lesions. Invasive diagnostic techniques performed on the lips carry a high risk of complications, but reflectance confocal microscopy (RCM), a non-invasive skin imaging technique, may change the current diagnostic pathway. This retrospective study was aimed at consolidating the RCM diagnostic criteria for AC and lip SCC. The study was conducted in two tertiary care centers in Bucharest, Romania. We included adults with histopathologically confirmed AC and SCC who also underwent RCM examination. Of the twelve lesions included in the study, four were AC and eight were SCC. An atypical honeycomb pattern and the presence of target cells in the epidermis were RCM features associated with AC. SCC was typified by the presence of complete disruption of the epidermal architecture and dermal inflammatory infiltrates. The mean blood vessel diameter in SCC was 18.55 µm larger than that in AC (p = 0.006) and there was no significant difference (p = 0.64) in blood vessel density, as measured by RCM, between SCC and AC. These data confirm that RCM can be useful for the in vivo distinction between AC and lip SCC.

Use of imaging techniques for melanocytic naevi and basal cell carcinoma in integrative analysis (Review)

Early detection of skin cancer is essential in order to obtain an improved prognosis. Clinicians need more objective and non-invasive examination methods to support their decision whether to biopsy or not tumoral lesions. These may include several imaging techniques such as dermoscopy, videodermoscopy, also known as sequential digital dermoscopy (SDD), computer-aided diagnosis (CAD), total body photography, imaging and high-frequency ultrasonography (HFUS), reflectance confocal microscopy, multiphoton tomography, electrical impedance spectroscopy, Raman spectroscopy, stepwise two-photon-laser spectroscopy and quantitative dynamic infrared. This review summarizes the current developments in the field of melanocytic lesions, such as naevi and basal cell carcinoma (BCC) imaging techniques. The aim was to collect and analyze data concerning types, indications, advantages and disadvantages of modern imaging techniques for in vivo skin tumor diagnosis. Two main methods were focused on, namely videodermoscopy and HFUS, which can be included in daily dermatologists' practice. In skin tumors HFUS allows the assessment of tumoral lesions with depth smaller than 1.5 cm, being described a correlation between ultrasonographic depth and the histologic index.

Tumour Microenvironment in Skin Carcinogenesis

Tumour microenvironment is a complex system comprising cells and molecules that will provide the necessary conditions for tumour development and progression. Cells residing in the tumour microenvironment gain specific phenotypes and specific functions that are pro-tumorigenic. Tumour progression is in fact a combination between tumour cell characteristics and its interplay with tumour microenvironment. This dynamic network will allow tumour cells to grow, migrate and invade tissues. In the present chapter, we are highlighting some traits that characterise tumour microenvironment in basal cell carcinoma, squamous cell carcinoma and cutaneous melanoma. In skin cancers, there are some common tumour microenvironment characteristics such as the presence of tumour-associated macrophages and regulatory T lymphocytes that are non-tumour cells promoting tumorigenesis. There are also skin cancer type differences in terms of tumour microenvironment characteristics. Thus, markers such as macrophage migration inhibitory factor in melanoma or the extraordinary diverse genetic make-up in the cancer-associated fibroblasts associated to squamous cell carcinoma are just a few of specific traits in skin cancer types. New technological advances for evaluation of tumour environment are presented. Thus, non-invasive skin imaging techniques such as reflectance confocal microscopy can evaluate skin tumour inflammatory infiltrates for density and cellular populations. Analysing tumour micromedium in depth may offer new insights into cancer therapy and identify new therapy targets.

Penile carcinoma and HPV infection (Review)

Penile carcinoma is a relatively frequent health issue in the developing countries such as Africa, Asia and South America, usually affecting men aged between 50 and 70 years. It is a highly treatable disease in its early stages, but has serious physical and psychological consequences. Usually, penile carcinoma is located in the penile glans, in approximately half the cases, with the most frequent histological type being squamous cell carcinoma with its microscopic subtypes. A large number of risk factors have been reported for this disease, having a multifactorial etiology, HPV infection being one of the most important factors involved in its appearance. Out of the HPV DNA positive genital cancers HPV-16 is the most frequently found type in men, followed by HPV-18. The evolution of penile cancer includes two independent carcinogenic pathways, related or unrelated to HPV infection. There is limited data available in literature regarding HPV-related neoplasia, as well as on the efficacy of vaccination in men, with studies still ongoing.

A Systematic Review and Meta-Analysis of the Accuracy of in VivoReflectance Confocal Microscopy for the Diagnosis of Primary Basal Cell Carcinoma

Basal cell carcinoma (BCC) is the most common cancer worldwide and its incidence is constantly rising. Early diagnosis and treatment can significantly reduce patient morbidity and healthcare costs. The value of reflectance confocal microscopy (RCM) in non-melanoma skin cancer diagnosis is still under debate. This systematic review and meta-analysis were conducted to assess the diagnostic accuracy of RCM in primary BCC. PubMed, Google Scholar, Scopus, and Web of Science databases were searched up to July 05, 2019, to collect articles concerning primary BCC diagnosis through RCM. The studies’ methodological quality was assessed by the QUADAS-2 tool. The meta-analysis was conducted using Stata 13.0, RevMan 5.0, and MetaDisc 1.4 software. We included 15 studies totaling a number of 4163 lesions. The pooled sensitivity and specificity were 0.92 (95% CI, 0.87–0.95; I² = 85.27%) and 0.93 (95% CI, 0.85–0.97; I² = 94.61%), the pooled positive and negative likelihood ratios were 13.51 (95% CI, 5.8–31.37; I² = 91.01%) and 0.08 (95% CI, 0.05–0.14; I² = 84.83%), and the pooled diagnostic odds ratio was 160.31 (95% CI, 64.73–397.02; I² = 71%). Despite the heterogeneity and risk of bias, this study demonstrates that RCM, through its high sensitivity and specificity, may have a significant clinical impact on the diagnosis of primary BCC.

In vivo Diagnosis of Primary Cutaneous Amyloidosis -the Role of Reflectance Confocal Microscopy

Primary cutaneous amyloidosis (PCA) is a form of localized amyloidosis. It is characterized by the deposition of a fibrillar material in the superficial dermis, without affecting other systems or organs. The diagnosis can be made clinically, but usually a skin biopsy is performed in order to exclude other skin diseases with similar appearance. Reflectance confocal microscopy (RCM) is a novel imaging tool that enables in vivo characterization of various skin changes with a high, quasi-microscopic resolution. This technique might have an important role in the differential diagnosis of cutaneous amyloidosis, by the in vivo assessment of epidermal changes and dermal amyloid deposition. Moreover, it is completely non-invasive and can be safely repeated on the same skin area. However, to date, there is only one published paper presenting the confocal features of primary cutaneous amyloidosis. Hereby, we describe the in vivo RCM features of PCA lesions from a patient with diabetes and correlate them with histologic findings. This strengthens the clinical usefulness of in vivo RCM examination for the non-invasive diagnosis of cutaneous amyloidosis, especially in patients that might associate diseases with impaired wound healing.

Current and future applications of confocal laser scanning microscopy imaging in skin oncology

Confocal laser scanning microscopy (CLSM) is a modern imaging technique that enables the in vivo or ex vivo characterization of skin lesions located in the epidermis and superficial dermis with a high quasi-microscopic resolution. Currently, it is considered to be the most promising imaging tool for the evaluation of superficial skin tumors. The in vivo mode adds the advantage of noninvasive, dynamic, in real-time assessment of the tumor associated vasculature and inflammation. It offers the possibility to repeatedly examine the same skin area without causing any damage and to monitor disease progression and treatment outcome. Furthermore, this novel technology allows the evaluation of the entire lesion and can be used to guide biopsies and to define tumor margins before surgical excision or other invasive therapies. CLSM diagnostic features may differentiate between the various histologic subtypes of skin tumors and therefore helps in choosing the best therapeutic approach. In this study, we present the CLSM characteristic features of the most common melanocytic and non-melanocytic skin tumors, as well as future possible CLSM applications in the study of experimental skin tumorigenesis on animal models.

Inflammation: A key process in skin tumorigenesis

The extremely delicate shift from an inflammatory process to tumorigenesis is a field of major scientific interest. While the inflammation induced by environmental agents has well known underlying mechanisms, less is known concerning the oncogenic changes that follow an inflammatory chronic status in the tissue microenvironment that can lead to pro-tumorigenic processes. Regardless of the origin of the environmental factors, the maintenance of an inflammatory microenvironment is a clear condition that favors tumorigenesis. Inflammation sustains the proliferation and survival of malignant transformed cells, can promote angiogenesis and metastatic processes, can negatively regulate the antitumoral adaptive and innate immune responses and may alter the efficacy of therapeutic agents. There is an abundance of studies focusing on molecular pathways that trigger inflammation-mediated tumorigenesis, and these data have revealed a series of biomarkers that can improve the diagnosis and prognosis in oncology. In skin there is a clear connection between tissue destruction, inflammation and tumor onset. Inflammation is a self-limiting process in normal physiological conditions, while tumor is a constitutive process activating new pro-tumor mechanisms. Among skin cancers, the most commonly diagnosed skin cancers, squamous cell carcinoma and basal cell carcinoma (BCC) have important inflammatory components. The most aggressive skin cancer, melanoma, is extensively research in regards to the new context of novel developed immune-therapies. In skin cancers, inflammatory markers can find their place in the biomarker set for improvement of diagnosis and prognosis.

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.

Non-invasive imaging techniques for the in vivo diagnosis of Bowen's disease: Three case reports

Bowen's disease (BD) is a relatively frequent non-melanoma skin cancer occurring mostly in elderly people. Until now, the usual way to establish the diagnosis is histopathological examination of a skin biopsy. Dermoscopy and reflectance confocal microscopy (RCM) are modern alternative methods that can be used as quick and non-invasive diagnostic techniques and as follow-up instruments in cases in which a conservative treatment is chosen for the management of BD. There are no very specific dermoscopic criteria for the diagnosis of this disease, but some dermoscopic features (scaly surface, vascular structures and pigmentation) can be found more frequent and can be helpful for the diagnosis. RCM of BD shows an acanthotic epidermis with two types of targetoid cells: the first, a large cell with bright center and dark peripheral halo, the second, a cell with dark center and a bright rim surrounded by a dark hallo, related with dyskeratotic cells on histological examination. BD management could be improved by using non-invasive, in vivo imaging techniques that allow a fast and easy diagnosis and can be used as follow-up tools. However, larger studies are necessary for the validation of our observations.

Vascular patterns in basal cell carcinoma: Dermoscopic, confocal and histopathological perspectives

Basal cell carcinoma (BCC) is the most prevalent skin cancer in the Caucasian population. A variety of different phenotypic presentations of BCC are possible. Although BCCs rarely metastasize, these tumors commonly destroy underlying tissues and should therefore be treated promptly. As vascular formation and angiogenesis are indicators of tumor development and progression, the presence of blood vessels, their morphology and architecture are important markers in skin lesions, providing critical information towards pathogenesis and diagnosis. BCC commonly lacks pigmentation, therefore it is important to emphasize the usefulness of vascular feature detection, recognition, quantification and interpretation. To answer the question of whether vascular patterns observed on dermoscopy, reflectance confocal microscopy (RCM) and histopathology might reflect the biologic behavior of BCCs, we undertook this review article. Several studies have sought, by various means, to identify vascular features associated with the more aggressive BCC phenotypes. Dermoscopic vascular pattern assessment can facilitate diagnostic discrimination between BCC subtypes, more aggressive BCCs displaying less or no pink coloration and a relative absence of central tumor vessels. RCM, a novel, non-invasive imaging technique, allows for the quantification of blood vessel size, density, and flow intensity in BCCs. BCCs are distinguished on RCM chiefly by vessels that branch and intertwine between neoplastic aggregates, a pattern strongly reflecting tumor neo-angiogenesis. The analysis of these vascular morphological and distribution patterns can provide further support in the diagnosis, assessment, or monitoring of BCCs. Histopathology shows significantly higher microvessel densities in the peritumoral stroma of BCCs, when compared to normal skin or benign tumors. This angiogenic response in the stroma is associated with local aggressiveness, therefore the quantification of peritumoralmicrovessels may further assist with tumor evaluation. How dermoscopy and RCM vascular patterns in BCC correlate with histopathological subtype and thus help in discriminating aggressive subtypes definitely deserves further investigation.

In vivo confocal laser scanning microscopy imaging of skin inflammation: Clinical applications and research directions

In vivo confocal laser scanning microscopy (CLSM) is a novel imaging technique that provides noninvasive, morphological characterization of skin structures with a resolution that is very close to that of light microscopy. Moreover, as it allows repeated imaging of the same skin area at different time-points, it is an excellent method for monitoring disease course, response to treatment or specific stimuli and a path to study dynamic phenomena in real-time. To date, two different variants of in vivo CLSM have been authorized in dermatological field, namely the reflectance confocal microscopy predominantly for clinical diagnosis and the fluorescence confocal microscopy mainly for research purposes. This study describes the principles of in vivo CLSM technique, its role in the diagnosis and monitoring of inflammatory skin diseases, as well as some promising research directions to study the dynamics of skin inflammation using this method. In vivo CLSM evaluation of inflammatory dermatoses and of the skin inflammatory component in various diseases has an undoubted potential with broad applications ranging from clinical, morphological to experimental, functional studies involving the skin.

Role of modern imaging techniques for the in vivo diagnosis of lichen planus

Lichen planus (LP) is a chronic inflammatory skin disease that can sometimes affect mucosal surfaces, with unknown pathogenesis, even though it appears to be an autoimmune disease. The diagnosis of lichen planus is usually based on histopathological examination of the lesions. Nowadays, the classical invasive diagnostic methods are replaced by modern non-invasive techniques. In this review, we present the main non-invasive imaging methods (dermoscopy, reflectance confocal microscopy, optical coherence tomography, ultrasound and diffuse reflection spectrophotometry) used in the diagnosis and therapeutic monitoring of lichen planus. Dermoscopy is a non-invasive method initially used for diagnosis of pigmented tumors but now is used also for inflammatory and infectious skin diseases. In lichen planus, the dermoscopy increases the accuracy of diagnosis, avoids skin biopsies commonly used and can be useful in the therapeutic monitoring by repeated investigation at different stages of treatment. Reflectance confocal microscopy (RCM) is a novel non-invasive imaging technique that is prevalently used for the diagnosis of skin tumors and inflammatory skin diseases. This technology has been mostly employed for bedside, real-time microscopic evaluation of psoriasis, lichen planus, contact dermatitis, revealing specific confocal features to support clinical diagnosis and assist with patient management. Optical coherence tomography (OCT) is an emergent imaging technique, developed over the last decade, based on the interaction of the infrared radiation (900–1,500 nm) and the living tissues. A limited information exists on the benefits of OCT technology for the in vivo diagnosis of LP but could be a useful auxiliary tool in the in vivo differential diagnosis, especially in clinical equivocal settings like mucosal lesions, and in monitoring the response to treatment. Our review shows the possibility of using modern imaging techniques for the in vivo diagnosis and also for evaluation of the treatment response.

Non-invasive imaging of actinic cheilitis and squamous cell carcinoma of the lip

An early diagnosis is of overwhelming importance for the management and prognosis of mucocutaneous cancer. Actinic cheilitis (AC), defined by the clonal expansion of genomically unstable keratinocytes, is the most common potentially malignant lesion affecting the lips. Squamous cell carcinoma (SCC) is the most frequent oral malignancy, and there is strong evidence that the majority of the SCCs of the lip originate from AC. There is considerable difficulty in discerning between dysplasia and invasive carcinomas solely on a clinical basis. Although dermoscopy has become an essential tool for skin tumor evaluation, reflectance confocal microscopy (RCM) is a non-invasive imaging technology that has proved itself extremely useful in the diagnosis and monitoring of several skin diseases, including AC and SCC. The present study aimed to re-emphasize the usefulness of RCM in the early detection of malignant transformation, using AC and SCC of the lips as working examples. Due to the apparent innocuousness of AC for numerous patients, it is not possible to overstress the importance of a correct and early diagnosis, proper treatment and long-term patient follow-up as being essential for preventing the progression to lip SCC, or for its timely diagnosis.

Assessment of dermal papillary and microvascular parameters in psoriasis vulgaris using in vivo reflectance confocal microscopy

In vivo reflectance confocal microscopy (RCM) is a modern, non-invasive imaging technique, which allows for real-time examination of the upper layers of the skin at a resolution similar to that of classic microscopy. In addition, it has the advantage of real-time evaluation of blood flow and dynamic monitoring of cutaneous changes while preserving tissue integrity. The present study reported on the in vivo RCM technique as an objective method for the noninvasive assessment of psoriasis vulgaris that is potentially applicable in clinical studies and in monitoring the evolution of lesions under treatment. In psoriasis lesions, RCM virtual horizontal sections at the level of the dermo-epidermal junction featured numerous and prominent dermal papillae that were not surrounded by bright rings of basal cells. Micromorphological examination of the lesions using this technique revealed that mean values of the section area, the perimeter and the Feret's diameter of the dermal papillae were significantly higher in psoriatic lesions than in normal skin. An increased number of capillary vessels per lesional dermal papilla as compared to healthy skin was observed. Furthermore, micromorphological parameters of dermal capillaries were increased in psoriatic skin. These observations point to the utility of in vivo RCM as a promising technique for the non-invasive diagnosis of psoriasis vulgaris, for monitoring the evolution of lesions at a micromorphological level under various treatments and for gaining a better understanding of the pathophysiological processes that occur in the evolution of this disease.

An overview of methods to mitigate artifacts in optical coherence tomography imaging of the skin

BACKGROUND

Optical coherence tomography (OCT) of skin delivers three-dimensional images of tissue microstructures. Although OCT imaging offers a promising high-resolution modality, OCT images suffer from some artifacts that lead to misinterpretation of tissue structures. Therefore, an overview of methods to mitigate artifacts in OCT imaging of the skin is of paramount importance. Speckle, intensity decay, and blurring are three major artifacts in OCT images. Speckle is due to the low coherent light source used in the configuration of OCT. Intensity decay is a deterioration of light with respect to depth, and blurring is the consequence of deficiencies of optical components.

METHOD

Two speckle reduction methods (one based on artificial neural network and one based on spatial compounding), an attenuation compensation algorithm (based on Beer-Lambert law) and a deblurring procedure (using deconvolution), are described. Moreover, optical properties extraction algorithm based on extended Huygens-Fresnel (EHF) principle to obtain some additional information from OCT images are discussed.

RESULTS

In this short overview, we summarize some of the image enhancement algorithms for OCT images which address the abovementioned artifacts. The results showed a significant improvement in the visibility of the clinically relevant features in the images. The quality improvement was evaluated using several numerical assessment measures.

CONCLUSION

Clinical dermatologists benefit from using these image enhancement algorithms to improve OCT diagnosis and essentially function as a noninvasive optical biopsy.

From Normal Skin to Squamous Cell Carcinoma: A Quest for Novel Biomarkers

Squamous cells carcinoma (SCC) is the second most frequent of the keratinocyte-derived malignancies after basal cell carcinoma and is associated with a significant psychosocial and economic burden for both the patient himself and society. Reported risk factors for the malignant transformation of keratinocytes and development of SCC include ultraviolet light exposure, followed by chronic scarring and inflammation, exposure to chemical compounds (arsenic, insecticides, and pesticides), and immune-suppression. Despite various available treatment methods and recent advances in noninvasive or minimal invasive diagnostic techniques, the risk recurrence and metastasis are far from being negligible, even in patients with negative histological margins and lymph nodes. Analyzing normal, dysplastic, and malignant keratinocyte proteome holds special promise for novel biomarker discovery in SCC that could be used in the future for early detection, risk assessment, tumor monitoring, and development of targeted therapeutic strategies.

Gene Expression and Proteome Analysis as Sources of Biomarkers in Basal Cell Carcinoma

Basal cell carcinoma (BCC) is the world's leading skin cancer in terms of frequency at the moment and its incidence continues to rise each year, leading to profound negative psychosocial and economic consequences. UV exposure is the most important environmental factor in the development of BCC in genetically predisposed individuals, this being reflected by the anatomical distribution of lesions mainly on sun-exposed skin areas. Early diagnosis and prompt management are of crucial importance in order to prevent local tissue destruction and subsequent disfigurement. Although various noninvasive or minimal invasive techniques have demonstrated their utility in increasing diagnostic accuracy of BCC and progress has been made in its treatment options, recurrent, aggressive, and metastatic variants of BCC still pose significant challenge for the healthcare system. Analysis of gene expression and proteomic profiling of tumor cells and of tumoral microenvironment in various tissues strongly suggests that certain molecules involved in skin cancer pathogenic pathways might represent novel predictive and prognostic biomarkers in BCC.