The Impact of In Vivo Reflectance Confocal Microscopy on the Diagnostic Accuracy of Lentigo Maligna and Equivocal Pigmented and Nonpigmented Macules of the Face

Abstract

Limited studies have reported the in vivo reflectance confocal microscopy (RCM) features of lentigo maligna (LM). A total of 64 RCM features were scored retrospectively and blinded to diagnosis in a consecutive series of RCM sampled, clinically equivocal, macules of the face (n=81 LM, n=203 benign macules (BMs)). In addition to describing RCM diagnostic features for LM (univariate), an algorithm was developed (LM score) to distinguish LM from BM. This comprised two major features each scoring +2 points (nonedged papillae and round large pagetoid cells > 20 microm), and four minor features; three scored +1 point each (three or more atypical cells at the dermoepidermal junction in five 0.5 x 0.5 mm(2) fields, follicular localization of atypical cells, and nucleated cells within the dermal papillae), and one (negative) feature scored -1 point (a broadened honeycomb pattern). A LM score of > or = 2 resulted in a sensitivity of 85% and specificity of 76% for the diagnosis of LM (odds ratio (OR) for LM 18.6; 95% confidence interval: 9.3-37.1). The algorithm was equally effective in the diagnosis of amelanotic lesions and showed good interobserver reproducibility (87%). In a test set of 29 LMs and 44 BMs, the OR for LM was 60.7 (confidence interval: 11.9-309) (93% sensitivity, 82% specificity).

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“…Langley et al [28] used the criteria to establish a CLSM diagnosis of melanoma and naevi they had described previously in their initial series [42]. Curchin C et al [32] followed the algorithms developed by Pellacani et al [43] for melanoma and by Guitera P et al [29] for lentigo maligna. Guitera P et al [29] worked on lentigo maligna (LM) and identified which CM features mentioned by Pellacani et al [44] can distinguish LM from benign macules.…”

“…In order to carry out meta-analysis the studies were split into three groups depending on the type of cancer that CLSM was used to detect. There were only two studies for the diagnosis of SCC [26,30], four and six studies for BCC [21,[30][31][32] and melanoma [27][28][29][30][31][32] respectively . The results of the studies for BCC and melanoma were pooled separately, as they were of clinically similar patients and methodologies.…”

“…not done on new set of patients were excluded. Finally eight studies [21,[26][27][28][29][30][31][32] met the criteria to be included for meta analysis. The evidence level of the studies was determined as per the NICE guidelines on development methods [33].…”

“…Average sensitivity, specificity, positive and negative predictive values from these studies is shown in Table 2. All selected studies had CLSM done on either a single or more than one type of skin cancer and normal peri-lesional skin [26] and/or benign lesions [21,[27][28][29][30][31][32]. The skin cancers included melanoma, BCC and SCC and the benign lesions included seborrheic keratosis [21,30], benign melanocytic lesions [21,[27][28][29][30][31][32], actinic keratosis [21,29,31,32], sebaceous hyperplasia [21], acne [21], rosacea [21], wart [21], molluscum contagiosum [21], cutaneous T cell lymphoma [21], eczema [21, dermatofibroma[21,30,31], tinea [21], vascular lesions [30] and Bowen's disease [31] etc.…”

“…The skin cancers included melanoma, BCC and SCC and the benign lesions included seborrheic keratosis [21,30], benign melanocytic lesions [21,[27][28][29][30][31][32], actinic keratosis [21,29,31,32], sebaceous hyperplasia [21], acne [21], rosacea [21], wart [21], molluscum contagiosum [21], cutaneous T cell lymphoma [21], eczema [21, dermatofibroma[21,30,31], tinea [21], vascular lesions [30] and Bowen's disease [31] etc. Five studies [21,[26][27][28][29] were done on one type of skin cancer. In 3 studies more than one skin cancer was included in the study population [30][31][32].…”