Melanocytic nevi with special features: clinical‐dermoscopic and reflectance confocal microscopic‐findings

Abstract

Histopathology is considered the 'gold' standard for the diagnosis and classification of melanocytic nevi, but the widespread use of in vivo diagnostic technologies such as dermoscopy and reflectance confocal microscopy (RCM), has enriched profoundly the knowledge regarding the morphological variability in nevi. This is because most morphological observations made via these in vivo tools are closely correlated with features seen in histopathology. Dermoscopy has allowed for a more detailed classification of nevi. As such, dermoscopy identifies four main morphologic groups (i.e. globular, reticular, starburst and structureless blue nevi), one group of nevi located at special body sites (i.e. face, acral, nail) and one group of nevi with special features. This latter category consists of nevi of the former categories, which are typified by peculiar clinical-histopathological findings. They can be subdivided into 'melanoma simulators' including combined nevi, recurrent nevi and sclerosing nevus with pseudomelanomatous features, 'targetoid' nevi (i.e. halo, cockade, irritated targetoid haemosiderotic and eczematous nevus) and uncommon histopathological variants such as desmoplastic, white dysplastic or ballon cell nevus. While the dermoscopic and RCM patterns of the former categories have been studied in detail, little is currently known about the clinical morphology of the heterogeneous group of 'special' nevi. In this article, we describe the clinical, dermoscopic and RCM features of 'special' nevi and review the current literature on this group of melanocytic proliferations.

Dermoscopy, Reflectance Confocal Microscopy and Immunohistochemical Analysis in Melanocytic Lesions with Meyerson's Phenomenon

“…Several studies showed diminished expression of interleukin-2 receptors in the lymphocytic infiltrate, suggesting that the involved mechanisms differ from those of allergic contact dermatitis [2,12]. Occasional eosinophils in the superficial dermis suggest a possible hypersensitivity process.…”

“…Meyerson's phenomenon can be confined to one, some or all nevi in a given patient. It was also described in association with some nonmelanocytic lesions, including seborrheic keratosis, histiocytofibroma, basal cell carcinoma, squamous cell carcinoma, sebaceous nevus, vascular malformations, insect bites, keloids and molluscum contagiosum [12,13,14,15]. Meyerson's nevi are more common in adult males, typically arising on the trunk and proximal extremities [1].…”

“…Meyerson's phenomenon does not modify the dermoscopic features of the involved melanocytic lesion, but the patterns are often blurred by a yellowish overlying superficial serocrust, therefore sometimes difficult to assess [12]. Longo et al [24] reported the RCM presentation of a Meyerson's nevus, describing epidermal spongiotic vesicles as round to ovoid dark spaces in the superficial epidermis, and features of melanocytic nevus in the dermoepidermal junction (DEJ) and papillary dermis.…”

Abundance of the benign melanocytic universe: Dermoscopic–histopathological correlation in nevi

“…Sclerosing nevi with pseudomelanomatous features or nevi with regression‐like fibrosis present a recently classified entity simulating regressing melanoma induced by minor trauma on pre‐existing nevi . These nevi are typically found on the convex area of the back of young to middle‐aged men . A typical trizonal pattern can be observed in histopathology: (i) atypical junctional proliferation and pagetoid spreading; (ii) atypical melanocytic nests within dermal sclerosis; and (iii) residual nevus tissue surrounding and within the cicatricial tissue.…”

Recurrent halo nevus: Dermoscopy and confocal microscopy features

“…Reflectance confocal microscopy (RCM) of HN has been previously described in 2 studies and some atypical features, also seen in atypical melanocytic lesions and malignant melanoma, were observed in most patients evaluated. These features included pagetoid cells, non-edged papilla, junctional thickening, nucleated cells in the dermal papillae, and plump bright cells 6, 7. These atypical findings might be due to local inflammation 7 …”