Dermoscopy of Lentiginous Melanomas and Equivocal Benign Pigmented Macules of the Scalp: A Case-Control Multicentric Study.
Dermatology 2023;
240:132-141. [PMID:
38035549 PMCID:
PMC10866176 DOI:
10.1159/000535030]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 11/02/2023] [Indexed: 12/02/2023] Open
Abstract
INTRODUCTION
Although the dermoscopic features of facial lentiginous melanomas (LM), including lentigo maligna and lentigo maligna melanoma, have been extensively studied, the literature about those located on the scalp is scarce. This study aims to describe the dermoscopic features of scalp LM and assess the diagnostic accuracy of dermoscopy to discriminate them from equivocal benign pigmented macules.
METHODS
Consecutive cases of scalp LM and histopathology-proven benign but clinically equivocal pigmented macules (actinic keratoses, solar lentigos, seborrhoeic keratoses, and lichen planus-like keratoses) from four referral centres were included. Dermoscopic features were analysed by two blinded experts. The diagnostic performance of a predictive model was assessed.
RESULTS
56 LM and 44 controls were included. Multiple features previously described for facial and extrafacial LM were frequently identified in both groups. Expert's sensitivity to diagnose scalp LM was 76.8% (63.6-87.0) and 78.6% (65.6-88.4), with specificity of 54.5% (38.9-69.6) and 56.8% (41.0-71.7), and fair agreement (kappa coefficient 0.248). The strongest independent predictors of malignancy were (OR, 95% CI) chaos of colour (15.43, 1.48-160.3), pigmented reticular lines (14.96, 1.68-132.9), increased density of vascular network (3.45, 1.09-10.92), and perifollicular grey circles (2.89, 0.96-8.67). The predictive model achieved 85.7% (73.8-93.6) sensitivity, 61.4% (45.5-75.6) specificity, and 81.5 (73.0-90.0) area under curve to discriminate benign and malignant lesions. A diagnostic flowchart was proposed, which should improve the diagnostic performance of dermoscopy.
CONCLUSION
Both facial and extrafacial dermoscopic patterns can be identified in scalp LM, with considerable overlap with benign pigmented macules, leading to low specificity and interobserver agreement on dermoscopy.
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