The specific dermoscopic criteria of Bowen's disease

British Association of Dermatologists guidelines for the management of people with cutaneous squamous cell carcinoma in situ (Bowen disease) 2022

The overall objective of the guideline is to provide up-to-date, evidence-based recommendations for the management of squamous cell carcinoma in situ (SCC in situ). The document aims to: offer an appraisal of all relevant literature up to 13th August 2021, focusing on any key developments; address important, practical clinical questions relating to the primary guideline objective; provide guideline recommendations and if appropriate research recommendations.

Dermoscopy as a Tool in Differentiating Cutaneous Squamous Cell Carcinoma From Its Variants

Background

Dermoscopic features of cutaneous squamous cell carcinoma (cSCC) have been widely studied, but their accuracy should be further investigated.

Objectives

This study assessed the diagnostic accuracy of a set of predetermined dermoscopic structures for 3 variants of cSCC, namely Bowen disease, keratoacanthoma and invasive cSCC.

Methods

Dermoscopic images of 56 histopathologically confirmed cSCC lesions (9 Bowen disease lesions, 7 keratoacanthomas, and 40 invasive cSCCs) were examined, and the diagnostic accuracy of dermoscopic structures was assessed. Discriminative ability of statistically significant positive predictors was determined using receiver operating characteristic (ROC) curves, and defined as an area under the ROC curve >0.700.

Results

Dermoscopic structures with statistical significance and discriminative ability were: for Bowen disease, clustered glomerular vessels and erosions; for keratoacanthoma, a central keratin plug; and for invasive cSCC, a mixed color of the background. Clustered and glomerular vessels had, for Bowen disease, perfect diagnostic accuracy, with: sensitivity of 88.9% for both features; specificity of 97.9% and 93.6%, respectively; positive predictive value (PPV) of 88.9% and 72.7%, respectively; and negative predictive value (NPV) of 97.8% for both. Erosions had, for BD, high specificity (87.2%) and NPV (91.1%), but low sensitivity (55.6%) and PPV (45.5%). A central keratin plug had, for keratoacanthoma, high specificity (87.8%) and NPV (93.5%), but low sensitivity (57.1%) and PPV (40%). A mixed background color had, for invasive cSCC, high specificity (81.3%) and PPV (89.7%), but low sensitivity (65%) and NPV (48.2%).

Conclusion

Dermoscopy accurately differentiates BD, through clustered glomerular vessels, from keratoacanthoma and invasive cSCC. Dermoscopic structures of keratoacanthoma and invasive cSCC overlap, and only histopathologic analysis differentiates them precisely.

Accuracy of dermoscopic criteria for the differentiation between superficial basal cell carcinoma and Bowen's disease

BACKGROUND

The dermoscopic features of superficial basal cell carcinoma (sBCC) and Bowen's disease (BD) have been extensively investigated, and dermoscopy was shown to significantly improve their recognition. However, incorrectly diagnosed cases still exist, with a considerable number of sBCCs dermoscopically interpreted as BD. Our aim was to investigate the dermoscopic variability in sBCC and BD on different anatomic sites, to identify potent dermoscopic predictors for each diagnosis and to investigate the potential source of the inaccurate clinico-dermoscopic diagnosis of some sBCCs.

METHODS

Dermoscopic images of histopathologically diagnosed sBCC and BD were evaluated by three independent investigators for the presence of predefined criteria. Subsequently, three independent investigators with expertise in dermoscopy classified the tumours as sBCC or BD based on the dermoscopic image. Diagnostic accuracy scores were calculated and crude and adjusted odds ratios, and 95% confidence intervals were calculated by univariate and conditional multivariate logistic regression, respectively.

RESULTS

A total of 283 lesions were included in the study (194 sBCCs and 89 BD). The main dermoscopic predictors of BD were dotted vessels (7.5-fold) and glomerular vessels (12.7-fold). The presence of leaf-like areas/spoke-wheel areas/concentric structures (OR = 0.027) and arborizing vessels (OR = 0.065) has predicted sBCC. Multivariate risk factors for sBCC misclassification were the location on lower extremities (OR = 5.5), the presence of dotted vessels (OR = 59.5) and the presence of large ulceration (OR = 6.4). In contrast, the presence of brown-coloured pigmentation was a protective predictor for misdiagnosis (OR = 0.007). Finally, a subgroup analysis of lesions located on lower extremities revealed two additional potent predictors of sBCC: superficial fine telangiectasia (SFT) and whity shiny blotches/strands.

CONCLUSIONS

Dotted and glomerular vessels are strong predictors of BD. When located on the lower extremities, sBCC may also display dotted vessels, rendering its recognition problematic. On the latter anatomic site, clinicians should consider SFT and whity shiny blotches/strands as additional sBCC predictors.

Precancerous Skin Lesions

Certain clinically and histologically recognizable skin lesions with a degree of risk of progression to squamous cell carcinoma have been traditionally grouped as precancerous skin conditions but now tend to be classified as in situ carcinomas. This consensus statement discusses various aspects of these lesions: their evaluation by means of clinical and histopathologic features, the initial evaluation of the patient, the identification of risk factors for progression, and the diagnostic and treatment strategies available today.

Vascular structures in dermoscopy

Dermoscopy is an aiding method in the visualization of the epidermis and dermis. It is usually used to diagnose melanocytic lesions. In recent years, dermoscopy has increasingly been used to diagnose non-melanocytic lesions. Certain vascular structures, their patterns of arrangement and additional criteria may demonstrate lesion-specific characteristics. In this review, vascular structures and their arrangements are discussed separately in the light of conflicting views and an overview of recent literature.

Non-invasive diagnostic techniques in the diagnosis of squamous cell carcinoma

Squamous cell carcinoma is the second most common cutaneous malignancy after basal cell carcinoma. Although the gold standard of diagnosis for squamous cell carcinoma is biopsy followed by histopathology evaluation, optical non-invasive diagnostic tools have obtained increased attention. Dermoscopy has become one of the basic diagnostic methods in clinical practice. The most common dermoscopic features of squamous cell carcinoma include clustered vascular pattern, glomerular vessels and hyperkeratosis. Under reflectance confocal microscopy, squamous cell carcinoma shows an atypical honeycomb or disarranged pattern of the spinous-granular layer of the epidermis, round nucleated bright cells in the epidermis and round vessels in the dermis. High frequency ultrasound and optical coherence tomography may be helpful in predominantly in pre-surgical evaluation of tumor size. Emerging non-invasive or minimal invasive techniques with possible application in the diagnosis of squamous cell carcinoma of the skin, lip, oral mucosa, vulva or other tissues include high-definition optical coherence tomography, in vivo multiphoton tomography, direct oral microscopy, electrical impedance spectroscopy, fluorescence spectroscopy, Raman spectroscopy, elastic scattering spectroscopy, differential path-length spectroscopy, nuclear magnetic resonance spectroscopy, and angle-resolved low coherence interferometry.

Dermoscopic characteristics of nodular squamous cell carcinoma and keratoacanthoma

Background:

Nodular squamous cell carcinoma (SCC) and keratoacanthoma (KA) may mimic a variety of other benign and malignant non-pigmented nodules.

Objectives:

To analyze the dermoscopic characteristics of nodular SCC and KA.

Patients/Methods:

Retrospective analysis of 50 nodular SCCs and 8 KAs collected from a tertiary dermatology referral center and a private dermatology practice in Melbourne, Australia, between 1 September 2009 and 1 October 2012. All lesions were nodules; defined as firm, elevated, round, palpable tumors with a diameter of 5 mm or more. Clinical and dermoscopic images were evaluated by two examiners in consensus.

Results:

Signs of keratinization were frequently observed and included keratin crust/scale (90% of SCCs, 100% of KAs), central keratin mass (32% of SCCs, 88% of KAs), white structureless areas (66% of SCCs, 50% of KAs), white circles (32% of SCCs, 38% of KAs) and white keratin pearls (14% of SCCs, 12% of KAs). Hemorrhage was present in 72% of SCCs and 88% of KAs and preferentially occurred centrally and in areas of keratinization. For nodular SCCs and KAs, we observed glomerular vessels (42% and 25% respectively), linear irregular vessels (36% and 25% respectively), atypical vessels (30% and 38% respectively) and hairpin vessels (30% and 25% respectively).

Conclusions:

Hemorrhage, keratinization and vascular features (glomerular, hairpin and linear irregular morphologies) are useful in diagnosing both nodular SCC and KA. Further research on the comparative dermoscopic characteristics of a range of amelanotic nodules is important in order to improve diagnosis of these clinically challenging tumors.

How to diagnose nonpigmented skin tumors: a review of vascular structures seen with dermoscopy: part II. Nonmelanocytic skin tumors

Nonmelanoma skin cancer refers to a broad class of tumors, including actinic keratosis, basal cell carcinoma, and squamous cell carcinoma, and as a group these are the most frequent cancers occurring in light skinned humans. In contrast to the rarity of amelanotic melanoma, nonmelanoma skin cancer commonly lacks pigmentation. Although these tumors rarely cause death related to metastases, they commonly destroy underlying tissues and should be removed at the earliest possible stage. Dermoscopy improves the clinical diagnosis of nonpigmented skin tumors by allowing the visualization of specific vascular structures that are usually not visible to the naked eye. Dermoscopic vascular patterns of several nonmelanocytic nonpigmented skin tumors, such as sebaceous hyperplasia, seborrheic keratosis, clear cell acanthoma, Bowen disease, or nodular cystic basal cell carcinoma are highly specific, allowing a ready diagnosis in most cases. Others, such as actinic keratosis, pyogenic granuloma, or uncommon adnexal tumors, may be difficult to differentiate even with the aid of dermoscopy. For this reason, general guidelines have been established to assist in making the most appropriate management decision. In the second part of this review of dermoscopic vascular structures of nonpigmented skin tumors, the dermoscopic patterns associated with benign and malignant nonmelanocytic skin tumors and recommendations for the management of these tumors will be discussed.

Dermoscopic features of Bowen's disease in Asians

BACKGROUND

Previously, dermoscopic features of Bowen's disease (BD) were extensively investigated in two studies, but there were some discrepancies. The dispute necessitated a further study concerning the dermoscopic features of BD.

OBJECTIVE

To describe the dermoscopic features of BD in Asians and to assess dermoscopy as a post-treatment monitoring tool of BD.

MATERIALS AND METHODS

Dermoscopic examinations of histopathologically diagnosed 26 BD lesions were performed to evaluate for the presence of various dermoscopic features. In addition, the correlating changes of dermoscopic features and histopathological results before and after treatments were assessed in five patients with BD.

RESULTS

Dermoscopically, 10 lesions were pigmented and 16 lesions were non-pigmented. The most frequent dermoscopic findings of BD were vascular structures (96%) and a scaly surface (96%). Among vascular structure, glomerular vessels were most frequently observed (77%). The other vascular structures in our study were linear irregular vessels, dotted vessels, polymorphous/atypical vessels and arborizing vessels. Among five patients who had been treated with either photodynamic therapy or 5% imiquimod cream, four patients revealed disappearance of dermoscopic vascular structures, but one patient showed remaining vascular structures after treatment. Skin biopsy from treated lesions disclosed clearance of BD in four patients who had no vascular structures but remaining BD in the patient whose dermoscopic finding displayed no disappearance of vascular structures.

CONCLUSIONS

Vascular structures, especially glomerular vessels plus a scaly surface, were common dermoscopic findings of BD in Asians. In addition, existence of dermoscopic vascular structures after treatment appears to be associated with residual disease.