Unusual Dermoscopic Patterns of Basal Cell Carcinoma Mimicking Melanoma

Unusual Dermoscopic Patterns of Basal Cell Carcinoma Mimicking Melanoma
Abstract:
Background: Basal cell carcinoma can simulate melanoma and specific dermoscopic criteria have not yet been defined in a large cohort.
Objective: To identify dermoscopic “trump” characteristics for differential diagnosis, identify cluster groups and assess the clinical impact of this study’s findings.
Methods: Retrospective, multicentric comparative study of atypical, non-facial basal cell carcinoma (≥1 seven-point checklist criteria) and melanoma (with at least one BCC criteria) at dermoscopy. Observed dermoscopic features were used to develop a proposed score. Lesion clusters were defined with hierarchical analysis. Clinical impact was assessed with a blinded reader study (diagnostic accuracy and confidence) following this study’s results.
Results: A total of 146 basal cell carcinoma and 76 melanoma were included. Atypical vascular pattern was common to most lesions (74.5%). Twelve trump features were included in the proposed score (sensitivity 94.1% and specificity 79.5%). Cluster analysis identified 3 basal cell carcinoma and 3 melanoma clusters. Findings improved overall diagnostic accuracy and confidence (26.8% and 13.8% respectively; p<0.001).
Limitations: Retrospective design and proposed score unvalidated.
Conclusions: Atypical vascular pattern should no longer be considered a melanoma associated feature only. Our proposed score improves diagnostic accuracy and confidence. Absence of pigmented features were associated with lower diagnostic accuracy and confidence.
Figure legends
Figure S1.BCC l Lesions representative of the hypo/amelanotic-MM like cluster: (a-c-e) clinical images;(b-d-f) white-red structureless areas (asterisk), (b-d-f) atypical vascular pattern (black circle), (b-d-f) superficial (short) fine telangiectasia (triangle), (b-d-f) ulceration (rectangle), (b-d-f) some arborizing vessels (arrows). ). MM, malignant melanoma; BCC, basal cell carcinoma.
Figure S2. BCC lesions representative of the mixed cluster: (a-c-e) clinical images; (b-f) superficial (short) fine telangiectasia (black triangle), (b-d-f) multiple blue-gray globules (asterisk), (b-d) atypical vascular pattern (white triangle), (b-f) white-red structureless areas (rectangle), (f) irregular dots/globules (arrows), (f) white streaks (circle). ). BCC, basal cell carcinoma.
Table legends
Table S1. Dermoscopic features classified according to common associations in literature with malignant melanoma (MM) and/or basal cell carcinoma (BCC) diagnoses
Table S2. Demographic and clinical details for the included patients.

模拟黑色素瘤（Melanoma）的基底细胞癌（Basal Cell Carcinoma）罕见皮肤镜模式
摘要：
背景：基底细胞癌（Basal Cell Carcinoma）可模拟黑色素瘤（Melanoma），目前尚无针对大队列人群的特异性皮肤镜诊断标准。
目的：明确可用于鉴别诊断的皮肤镜决定性特征，确定病变聚类分组，并评估本研究结果的临床应用价值。
方法：本研究为回顾性多中心对照研究，纳入经皮肤镜检查的非典型非面部基底细胞癌（满足≥1项七点评分检查表标准）及黑色素瘤（至少符合1项基底细胞癌诊断标准）病例。通过观察所得的皮肤镜特征拟定评分体系，采用层级聚类分析定义病变聚类组，并通过盲法阅片研究（诊断准确率与诊断置信度）评估本研究结果的临床应用价值。
结果：本研究共纳入146例基底细胞癌病例与76例黑色素瘤病例。非典型血管模式在多数病变中均可见（74.5%）。拟定的评分体系共纳入12项关键特征，灵敏度为94.1%，特异度为79.5%。聚类分析共识别出3组基底细胞癌病变与3组黑色素瘤病变。本研究结果可提升整体诊断准确率与诊断置信度（分别提升26.8%与13.8%；p<0.001）。
局限性：本研究为回顾性设计，且拟定的评分体系尚未经过验证。
结论：非典型血管模式不应再仅被视为黑色素瘤相关的特征。本研究拟定的评分体系可提升诊断准确率与置信度。无色素性特征与较低的诊断准确率及置信度相关。
图注：
图S1：模拟低色素/无色素性恶性黑色素瘤（Malignant Melanoma, MM）聚类的基底细胞癌（Basal Cell Carcinoma, BCC）病变：(a-c-e) 临床图像；(b-d-f) 白红色无结构区域（星号标注）、(b-d-f) 非典型血管模式（黑色圆圈标注）、(b-d-f) 浅表（短）细毛细血管扩张（三角标注）、(b-d-f) 溃疡（矩形标注）、(b-d-f) 部分树枝状血管（箭头标注）。其中MM为恶性黑色素瘤，BCC为基底细胞癌。
图S2：混合聚类代表性基底细胞癌（Basal Cell Carcinoma, BCC）病变：(a-c-e) 临床图像；(b-f) 浅表（短）细毛细血管扩张（黑色三角标注）、(b-d-f) 多发蓝灰色小球（星号标注）、(b-d) 非典型血管模式（白色三角标注）、(b-f) 白红色无结构区域（矩形标注）、(f) 不规则点状/球状结构（箭头标注）、(f) 白色条纹（圆圈标注）。其中BCC为基底细胞癌。
表注：
表S1：根据文献中与恶性黑色素瘤（Malignant Melanoma, MM）和/或基底细胞癌（Basal Cell Carcinoma, BCC）诊断相关的常见关联分类的皮肤镜特征
表S2：纳入研究患者的人口统计学与临床细节