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[4 min read] Dermoscopic criteria differentiation between BCC and Bowen’s disease
The dermoscopic features of superficial basal cell carcinoma (BCC) and Bowen’s disease have been extensively investigated, and dermoscopy was shown to significantly improve their recognition. However, incorrectly diagnosed cases still exist, with a considerable number of BCCs dermoscopically interpreted as Bowen’s disease.
A 2018 study conducted by HealthCert presenters Aimilios Lallas and Zoe Apalla et al aimed to investigate the dermoscopic variability in BCC and Bowen’s disease 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 BCCs.
Dermoscopic images of histopathologically diagnosed BCC and Bowen’s disease were evaluated by three independent investigators for the presence of predefined criteria. Subsequently, three independent investigators with expertise in dermoscopy classified the tumours as BCC or Bowen’s disease based on the dermoscopic image. Diagnostic accuracy scores were calculated and crude and adjusted odds ratios, and 95 per cent confidence intervals were calculated by univariate and conditional multivariate logistic regression, respectively.
A total of 283 lesions were included in the study (194 BCCs and 89 Bowen’s disease). The main dermoscopic predictors of Bowen’s disease 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 BCC.
Multivariate risk factors for BCC 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 BCC: superficial fine telangiectasia and white shiny blotches/strands.
To conclude, the study surmised that dotted and glomerular vessels are strong predictors of Bowen’s disease. When located on the lower extremities, BCC may also display dotted vessels, rendering its recognition problematic. On the latter anatomic site, clinicians should consider superficial fine telangiectasia and white shiny blotches/strands as additional BCC predictors.