Dermoscopy and Reflectance Confocal Microscopy to Estimate Breslow Index and Mitotic Rate in Primary Melanoma

Abstract

Introduction: Non-invasive imaging techniques offer the possibility to optimize the first approach to melanoma. Reflectance Confocal Microscopy (RCM) has a promising role in predicting the main prognostic events in the dermo-epidermal and papillary dermis.

Objectives: To identify pre-surgical criteria that can predict the main prognostic features of melanoma.

Methods: A retrospective cohort-study evaluated dermoscopic, confocal and histopathological characteristics of consecutively diagnosed sporadic melanomas. RCM-melanoma patterns classified into 1) dendritic-cell, 2) round-cell, 3) dermal nest and 4) combined type. Acral, facial and mucosal locations were excluded.

Results: Ninety-two primary melanomas were included: 44 males and 48 females (mean age 60.4 years, standard deviation [SD] 16.2) with a mean Breslow of 1.43 mm (SD 1.6). The most frequent dermoscopic presentation was the multicomponent pattern, the predominant confocal pattern was dendritic-cell type (44.6%). The presence of pigmented network on dermoscopy was related to lower Breslow and mitotic rates (both P = 0.002); in contrast to the presence of visible vessels, which was related to higher Breslow and mitotic indexes (both P = 0.001). Confocal observation of dermal nests or atypical cells in the papillary dermis was related to a higher mitotic rate (P = 0.006 and P = 0.03, respectively). Similarly, diffuse inflammatory infiltrates visible in the superficial dermis was associated with higher Breslow (P = 0.04) and mitotic index (P = 0.04).

Conclusions: Dermoscopic and RCM in vivo findings on primary melanoma correlate with histopathologic Breslow index, mitotic rate and tumor infiltrating lymphocytes. The architecture and cytology of primary melanoma can be estimated by combining dermoscopy and RCM prior to excision.

Keywords: Breslow index; confocal microscopy; melanoma; mitotix rate; prognostic markers.

Figure 1

Dermoscopic and Confocal findings in primary melanoma. (A) Clinical appearance of pigmented asymmetric lesion on the leg. (B)Dermoscopic presence of asymmetric polychromic lesion, showing negative network (white square), bluewhite veil, atypical vessels (red square), ulceration and structureless pigmented areas. (C) Reflectance Confocal Microscopy (RCM) imaging (800microns×800micros) at dermoepidermal junction (DEJ) and superficial dermis showing cerebriform nests with amorphous pleomorphic cells. Non edged papillae and atypical cells were visible at DEJ. (D) RCM imaging (1mm×1mm) at superficial dermis demonstrated multiple atypical high caliber vessels (red squares).

Figure 2

Confocal and histopathological correlation of primary melanoma. (A) Clinical image of superficial spreading ulcerated melanoma on the thigh of a lady in her 60s. (B) Reflectance confocal microscopy (RCM) single image (0.5 mm × 0.5 mm) at superficial epidermis layer, multiple dendritic and roundish pagetoid cells (combined type melanoma). (C) RCM mosaic imaging (1.5 mm × 1.5 mm) at suprabasal epidermal layer; multiple dendritic and roundish atypical cells. (D) RCM mosaic imaging (1.5mm × 1.5 mm) at DEJ and papillary dermis; atypical dendritic and pleomorphic cells at DEJ isolated and forming junctural nests and junctural thickenings, with non-edged papillae. (E) Histopathological (H&E) (x40) demonstrated ulcerated superficial spreading melanoma with vertical growth, Breslow 2mm. (F) Histopathological (H&E) (x100) correlated with nesting tendency and mitotic index of 10/mm².