Negative Pigment Network Identifies a Peculiar Melanoma Subtype and Represents a Clue to Melanoma Diagnosis: A Dermoscopic Study of 401 Melanomas

Abstract

The dermoscopic descriptor "negative pigment network" (NPN) has been reported in several types of melanocytic and non-melanocytic lesions, although it has a higher frequency of association with melanoma and Spitz naevus. In a study of 401 consecutive melanomas, excluding facial, acral and mucosal locations, the frequency and variability of NPN were investigated, and the results of NPN correlated with clinical and histopathological data. NPN of any extension was found in 27% of melanomas, most frequently invasive and arising from a naevus on the trunk of young subjects. Seven percent of melanomas in the study population showed presence of NPN in more than half of the lesion area; most of these did not show typical dermoscopic melanoma features. The authors propose a new melanoma subtype, in which extensive NPN should be considered as a diagnostic indicator.

Rapidly Growing Pigmented Lesion in a 13‐Year‐Old Girl

“…Negative pigment network (NPN), as seen in our case, also known as reticular depigmentation or inverse network, consists of serpiginous hypopigmented interconnecting lines that surround elongated and irregularly shaped curvilinear brown globular structures . NPN is a worrisome feature, found in 27% and 34% of melanomas in two large series . Spitz nevi are more likely to harbor a negative network that is symmetrically distributed within the lesion, whereas melanomas are more likely to display an eccentric or heterogeneous negative network.…”

Investigation of the relationship between dermoscopic features and histopathological prognostic indicators in patients with cutaneous melanoma

“…Benign lezyonlarda bal peteği tarzında düzenli görünen pigment ağı, melanomlarda dermoepidermal bileşkedeki atipik melanositik hiperplaziye bağlı olarak düzensiz, kalın ve geniştir 1 . Yapılan araştırmalarda atipik pigment ağının in situ melanomlarda %88, invaziv melanomlarda ise %33 oranında görüldüğü ve çok erken dönemdeki melanomları temsil ettiği bildirilmektedir 23,25 . Bizim olgularımızda da literatür bulgularıyla uyumlu olarak atipik pigment ağının ince melanomlarda anlamlı olarak daha sık izlendiği belirlenmiştir.…”

A comparative dermoscopic and reflectance confocal microscopy study of naevi and melanoma with negative pigment network

“…A limited extent of the NPN (<20% of lesion area) was associated with an in situ melanoma, while among invasive melanomas, NPN was more widely distributed . Interestingly, 7% of melanomas showed widespread NPN in over 50% of the lesion area, in the absence of other melanoma‐specific features; these NPN‐melanomas arose in younger patients and mimicked Spitz naevi …”

“…studied 401 consecutive melanomas and found NPN in 27% of cases, mostly among invasive melanomas (31%) compared with in situ melanomas (16%); melanomas with NPN were associated with a naevus more commonly (37%) than melanomas without NPN (23%). A centrally located NPN was infrequent among melanomas (7%), while most melanomas (63%) showed variability in the width and shape of the white lines and the pigmented clods of the NPN . A limited extent of the NPN (<20% of lesion area) was associated with an in situ melanoma, while among invasive melanomas, NPN was more widely distributed .…”

“…A centrally located NPN was infrequent among melanomas (7%), while most melanomas (63%) showed variability in the width and shape of the white lines and the pigmented clods of the NPN . A limited extent of the NPN (<20% of lesion area) was associated with an in situ melanoma, while among invasive melanomas, NPN was more widely distributed . Interestingly, 7% of melanomas showed widespread NPN in over 50% of the lesion area, in the absence of other melanoma‐specific features; these NPN‐melanomas arose in younger patients and mimicked Spitz naevi …”