Hotspot analysis by confocal microscopy can help to differentiate challenging melanocytic skin lesions

Abstract

Some melanocytic lesions do not present enough clinical and dermoscopic features to allow ruling out a possible melanoma diagnosis. These “doubtful melanocytic lesions” pose a very common and challenging scenario in clinical practice and were selected at this study for reflectance confocal microscopy evaluation and subsequent surgical excision for histopathological diagnosis. The study included 110 lesions and three confocal features were statistically able to distinguish benign melanocytic lesions from melanomas: “peripheral hotspot at dermo-epidermal junction”, “nucleated roundish cells at the dermo-epidermal junction” and “sheet of cells”. The finding of a peripheral hotspot (atypical cells in 1mm2) at the DEJ is highlighted because has not been previously reported in the literature as a confocal feature related to melanomas.

Presentation of Meibomian Acini Compared to Dermal Papillae of the Eyelid Margin, Using Confocal Laser Scanning Microscopy and Corresponding Histology

“…The undulating form of the DEJ provides an anchor for the epidermis and increases the strength of adhesion between the two layers 19 . In dermatology, in vivo CLSM has been used for decades to study characteristic features of skin morphology and pathological alterations, including detailed descriptions of the papillary dermis 16 , 20 , 21 . The high morphological similarity of the structures demonstrated as dermal papillae in dermatological studies with the structures previously presented as MGs in ophthalmological experiments might suggest that the latter structures are also the cross-sectional image of the dermal papillae 22 , 23 .…”

Confocal microscopy – Working principle and applications in dermatology

“…[23] Castro et al, after studying 110 lesions that were clinically and dermoscopically suspicious of superficial spreading melanoma, reported three RCM features that showed statistically significant association with melanomas and they included "peripheral hotspot at the dermo-epidermal junction (defined as 1 mm × 1 mm area of the lesion where atypical cells are more aggregated), " "nucleated roundish cells at the dermo-epidermal junction, " and "sheet of cells. " [24] Handheld RCM is used to determine the tumor extent before definitive surgery. ere was an overall 85.9% agreement between margin assessment by RCM and final histopathology.…”