Publication date: Jul 08, 2019
Negative pigment network (NPN) is a dermoscopic structure observed more frequently among melanomas than nevi. Precise tissue correlates of NPN are still elusive.
To describe the reflectance confocal microscopy (RCM) findings underlying NPN in melanocytic neoplasms.
We retrospectively identified all melanocytic neoplasms displaying dermoscopic NPN that were imaged with RCM and subsequently biopsied between 2011-2015. Images from study lesions (n=50) were evaluated for dermoscopic and RCM Criteria. Histopathological correlational study was performed in a subset of cases (n=15).
The study dataset consisted of 21 melanomas (42%) and 29 nevi (58%). melanomas showed more frequently irregularly-shaped globules than nevi (61.9% vs. 27.6%, p=0.03); NPN also tended to be more asymmetrically located among melanomas (85.7%) than nevi (62.1%), albeit not significant (p=0.06). Under RCM, we observed three patterns of dermal papillae (DP): (1) “Dark DPs” – whereby DPs were devoid of nests and often surrounded by a junctional proliferation as thick-Rings – this pattern was less common among melanomas (n=10, 48%) than nevi (n=23, 79%, p=0.02); (2) “Bulging DPs” – whereby junctional nests of melanocytes protrude into the DPs, often in association with junctional proliferation as Meshwork – with comparable frequency among melanomas (n=12, 57%) and nevi (n=23, 79%, p=0.09) and (3) “Expanded DPs” – whereby junctional and / or dermal nests filled and expanded the DPs, often in association with dermal-epidermal junction (DEJ) Clod pattern – seen more commonly among melanomas (n=15, 71%) than nevi (n=6, 21%, p
Farnetani, F., Scope, A., Mazzoni, L., Mandel, V.D., Manfredini, M., Magi, S., Vaschieri, C., Kaleci, S., Longo, C., Ciardo, S., , Stanganelli, and Pellacani, G. A comparative dermoscopic and reflectance confocal microscopy study of nevi and melanoma with negative pigment network. 23324. 2019 J Eur Acad Dermatol Venereol.