The use of reflectance confocal microscopy for examination of benign and malignant skin tumors

Cutaneous Imaging Techniques

Cutaneous imaging is a central tenant to the practice of dermatology. In this article, the authors explore various noninvasive and invasive skin imaging techniques, as well as the latest deployment of these technologies in conjunction with the use artificial intelligence and machine learning. The authors also provide insight into the benefits, limitations, and challenges around integrating these technologies into dermatologic practice.

Functional and molecular 3D mapping of angiosarcoma tumor using non-invasive laser speckle, hyperspectral, and photoacoustic imaging

PURPOSE

The gold standard for skin cancer diagnosis is surgical excisional biopsy and histopathological examination. Several non-invasive diagnostic techniques exist, although they have not yet translated into clinical use. This is a proof-of-concept study to assess the possibility of imaging an angiosarcoma in the periocular area.

METHODS

We use laser speckle, hyperspectral, and photoacoustic imaging to monitor blood perfusion and oxygen saturation, as well as the molecular composition of the tissue. The information obtained from each imaging modality was combined in order to yield a more comprehensive picture of the function, as well as molecular composition of a rapidly growing cutaneous angiosarcoma in the periocular area.

RESULTS

We found an increase in perfusion coupled with a reduction in oxygen saturation in the angiosarcoma. We could also extract the molecular composition of the angiosarcoma at a depth, depicting both the oxygen saturation and highlighting the presence of connective tissue via collagen.

CONCLUSIONS

We demonstrate the different physiological parameters that can be obtained with the different techniques and how these can be combined to provide detailed 3D maps of the functional and molecular properties of tumors useful in preoperative assessment.

Lentigo maligna: a review

Lentigo maligna (LM) is a melanoma in situ with distinct clinical features and histology. It commonly affects men after the sixth decade of life. Incidence rates of LM have increased based on early 21st century data from different countries; however, data are suboptimal. Data from England show a plateauing crude incidence between 2013 and 2019. By comparison, invasive melanoma and other types of melanoma in situ commonly appears in younger age groups (median age 58 and 67 years old, respectively) and incidence is rising. The most important risk factors for LM include fair skin and cumulative ultraviolet solar radiation exposure. Although LM is limited to the epidermis and connected skin adnexa, it may progress to invasive LM melanoma. The reported rate of malignant progression varies, reflecting a challenge for LM epidemiology research as often lesions are removed on diagnosis. LM poses a challenge in diagnosis and management. Although it can be diagnosed clinically or dermoscopically, histopathological assessment of biopsied skin tissue remains the gold standard. Reflectance confocal microscopy allows for better appreciation of the complexity of LM at a cellular level, often progressing beyond clinical margins. Management of LM may involve Mohs micrographic surgery or excision, although recurrence may occur even with 5 mm clinical margins. Imiquimod cream may be effective, but incomplete treatment and recurrence has been reported. Conservative management with observation or radiotherapy may be used in selected patients' cases. Five-year net survival rates are excellent. This paper reviews the natural history, epidemiology, aetiology, pathogenesis, diagnosis and management of LM.

Reciprocal Interplay Between Fibrillar Collagens and Collagen-Binding Integrins: Implications in Cancer Progression and Metastasis

Cancers are complex ecosystems composed of malignant cells embedded in an intricate microenvironment made of different non-transformed cell types and extracellular matrix (ECM) components. The tumor microenvironment is governed by constantly evolving cell-cell and cell-ECM interactions, which are now recognized as key actors in the genesis, progression and treatment of cancer lesions. The ECM is composed of a multitude of fibrous proteins, matricellular-associated proteins, and proteoglycans. This complex structure plays critical roles in cancer progression: it functions as the scaffold for tissues organization and provides biochemical and biomechanical signals that regulate key cancer hallmarks including cell growth, survival, migration, differentiation, angiogenesis, and immune response. Cells sense the biochemical and mechanical properties of the ECM through specialized transmembrane receptors that include integrins, discoidin domain receptors, and syndecans. Advanced stages of several carcinomas are characterized by a desmoplastic reaction characterized by an extensive deposition of fibrillar collagens in the microenvironment. This compact network of fibrillar collagens promotes cancer progression and metastasis, and is associated with low survival rates for cancer patients. In this review, we highlight how fibrillar collagens and their corresponding integrin receptors are modulated during cancer progression. We describe how the deposition and alignment of collagen fibers influence the tumor microenvironment and how fibrillar collagen-binding integrins expressed by cancer and stromal cells critically contribute in cancer hallmarks.

Dermoscopic features in different dermatopathological stages of cutaneous melanomas

Introduction

Due to the rising incidence of cutaneous melanoma there is a great need for the development of new diagnostic techniques as well as the improvement of those that are already well known, such as dermoscopy. Since early detection and a proper technique for excising the tumor are crucial for patients' survival, early staging of the tumor is very important.

Aim

To investigate whether there is a significant difference between the presence of selected dermoscopic features compared to the location on the skin and pathology results: Breslow's depth, mitotic index and ulceration.

Material and methods

We examined videodermoscopic images of cutaneous melanomas in 81 patients and compared their features with the histological results such as Breslow's depth, mitotic index and ulceration. In the study, we divided and compared the tumors in groups: in situ and invasive, ≤ 1.0 mm and > 1.0 mm thick on the Breslow scale.

Results

In the study we observed statistically significantly higher prevalence of pseudopods (30.5%) and multicomponent pattern (69.5%) in invasive melanomas in comparison to in situ melanomas (9.1% and 36.4% respectively). White regression structures were more commonly described in invasive melanomas thicker than 1.0 mm on Breslow's scale. Atypical blood vessels and nodules were more specific to invasive melanomas with ulcerations and mitotic index ≥ 1. The atypical pigment network was more specific for thin invasive melanomas.

Conclusions

Presence of pseudopods, a multicomponent pattern, white regression structures, atypical blood vessels and nodules on dermoscopy suggest invasive (high stage) melanoma.

Evaluation of Syringomas by In Vivo Reflectance Confocal Microscopy: A Report of Two Cases

Syringomas are benign adnexal tumors that are characterized histologically by the presence of small solid and cystic epithelial structures in the upper half of the reticular dermis. Reflectance confocal microscopy is a noninvasive diagnostic method that enables in vivo visualization of tissues with a resolution that approximates that of conventional histopathology. The use of this method in skin imaging over the past several years has improved dermatological diagnoses, creating the potential for its wide application in such diagnoses, especially for benign and malignant skin tumors. We describe its use in the diagnosis of syringoma in 2 patients and correlate the resulting clinical, histopathological, and digital reflectance confocal microscopy images.

One Step Melanoma Surgery for Patient with Thick Primary Melanomas: "To Break the Rules, You Must First Master Them!"

BACKGROUND:

We present to the attention of the medical, dermatological and oncosurgical community data that serves to indicate the indispensability of optimisation of the algorithm and recommendations for diagnosis and surgical treatment of cutaneous melanoma. These recommendations could be referred to different subgroups of patients in different clinical stages as well as to patients with different initial characterisation (histological morphology) of the primary tumours. One step surgery is not a myth, even more, it could prove to be one of the best solutions for some patient collectives with advanced stages of melanoma.

CASE REPORT:

We present a case of a 74 - year old patient with a congenital medium sized melanocytic nevus, located directly above the lateral part of the elbow joint. In one month and a half, an achromatic nodular formation evolves with a diameter of 2.7 x 2.3 cm, prominent over the skin level, painful by palpation and spontaneously bleeding. By the anamnestic, clinical and dermoscopic findings the patient was diagnosed with nodular melanoma associated with a congenital medium sized melanocytic nevus. A primary excision with a field of safety 0.5 cm in all directions was performed. After confirmation of the primary diagnosis (tumour thickness 8 mm with no ultrasonographic detection of enlarged lymph nodes), seven days later are - excision was performed with an additional field of surgical safety of 1.5 cm in all directions.

CONCLUSIONS:

In this case remains unclear the following question: For what reason a preoperative high - frequent ultrasonography (HFUS) is not recommended to be used as it will allow only one surgical excision with the elimination of a tumour with a safety field of 2cm in all directions? The enigma about the obstacles preventing such a rational optimisation of the current diagnostic and therapeutic algorithm in patients with melanomas remains unresolved. One step surgery for cutaneous melanoma is widely used in many countries although it continues to be considered as a matter of dispute for some experts. Once again, by a clinical case and the following analysis, we would like to focus the attention of the dermatosurgical community on this crucial and highly significant problem. Innovations are very often resulting from the simplicity of logic, which unfortunately is not always accepted appropriately.

Optical coherence tomography for the diagnosis of malignant skin tumors: a meta-analysis

Optical coherence tomography (OCT) is an emergent imaging tool used for noninvasive diagnosis of skin diseases. The present meta-analysis was carried out to assess the accuracy of OCT for the diagnosis of skin cancer. We conducted a systematic literature search though EMBASE, Medline, PubMed, the Cochrane Library, and Web of Science database for relevant articles published up to June 6, 2017. The quality of the included studies was assessed using the QUADAS-2 tool and the Oxford Levels of Evidence Scale. Statistical analyses were conducted using the software Meta-Disc version 1.4 and STATA version 12.0. A total of 14 studies involving more than 813 patients with a total of 1958 lesions were included in our analyses. The pooled sensitivity and specificity of OCT for skin cancer diagnoses were 91.8% and 86.7%, respectively. Subgroup analysis showed that the pooled sensitivities of OCT for detecting basal cell carcinoma (BCC), squamous cell carcinoma (SCC), actinic keratosis, and malignant melanoma were 92.4%, 92.3%, 73.8%, and 81.0%, respectively. The pooled specificities were 86.9%, 99.5%, 91.5%, and 93.8%, respectively. OCT appears to be useful for the detection of BCC and SCC. It is a valuable diagnostic method when screening for early skin cancers.

Optical detection and monitoring of pigmented skin lesions

A method is presented for discriminating between malignant and benign pigmented skin lesions based on multispectral and multi-angle images. It is discussed how to retrieve maps of physiology properties and morphometric parameters from recorded images using a bio-optical model, radiative transfer calculations, and nonlinear inversion, and how to employ automated zooming to extract lesion and surrounding masks. Training and validation of a classification scheme for separation between benign and malignant tissue yielded sensitivity/specificity ranging from 97%/97% for application to a small dataset comprised of lesions not used for training and validation to 99%/93% for application to a larger dataset.

The potential role of in vivo reflectance confocal microscopy for evaluating oral cavity lesions: a systematic review

BACKGROUND

Since the early 2000s, several studies have examined the application of reflectance confocal microscopy (RCM) to the oral cavity. This review gives an overview of the literature on reflectance confocal microscopy analysis of the oral cavity in vivo and identifies flaws in the studies, providing guidance to improve reflectance confocal microscopy applications and inform the design of future studies.

METHODS

The PubMed, ISI, Scopus, and Cochrane Library databases were searched for publications on RCM using the terms 'reflectance confocal microscopy' in combination with 'mouth' and other terms related to the topic of interest.

RESULTS

The search gave 617 results. Seventeen studies were included in our final analysis. We decided to organize the selected articles according to four topics: healthy mucosa, autoimmune diseases, cancer and precancerous lesions, and hard dental tissues.

CONCLUSION

Although reflectance confocal microscopy is promising for diagnosing and monitoring oral pathology, it has shortcomings and there are still too few publications on this topic. Further studies are needed to increase the quantity and quality of the results, to translate research into clinical practice.

A comparative study of the effects of retinol and retinoic acid on histological, molecular, and clinical properties of human skin

BACKGROUND

All-trans retinol, a precursor of retinoic acid, is an effective anti-aging treatment widely used in skin care products. In comparison, topical retinoic acid is believed to provide even greater anti-aging effects; however, there is limited research directly comparing the effects of retinol and retinoic acid on skin.

OBJECTIVES

In this study, we compare the effects of retinol and retinoic acid on skin structure and expression of skin function-related genes and proteins. We also examine the effect of retinol treatment on skin appearance.

METHODS

Skin histology was examined by H&E staining and in vivo confocal microscopy. Expression levels of skin genes and proteins were analyzed using RT-PCR and immunohistochemistry. The efficacy of a retinol formulation in improving skin appearance was assessed using digital image-based wrinkle analysis.

RESULTS

Four weeks of retinoic acid and retinol treatments both increased epidermal thickness, and upregulated genes for collagen type 1 (COL1A1), and collagen type 3 (COL3A1) with corresponding increases in procollagen I and procollagen III protein expression. Facial image analysis showed a significant reduction in facial wrinkles following 12 weeks of retinol application.

CONCLUSIONS

The results of this study demonstrate that topical application of retinol significantly affects both cellular and molecular properties of the epidermis and dermis, as shown by skin biopsy and noninvasive imaging analyses. Although the magnitude tends to be smaller, retinol induces similar changes in skin histology, and gene and protein expression as compared to retinoic acid application. These results were confirmed by the significant facial anti-aging effect observed in the retinol efficacy clinical study.