Pigment network

From dermoscopedia

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 Editor: Ralph P. Braun

 Author(s): Oriol Yélamos     ·  Katrin Kerl     ·  Ralph P. Braun
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Description In this cover we describe the dermoscopyThe examination of [skin lesions] with a 'dermatoscope'. This traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections. criterion pigment networkThis glossary term has not yet been described. and its variants such as pseudonetworkA structureless pigment area interrupted by non-pigmented adnexal openings, atypical pigment networkNetwork with increased variability in the color, thickness, and spacing of the lines of the network; asymmetrically distributed; gray color and typical pigment networkNetwork with minimal variability in the color, thickness, and spacing of the lines; symmetrically distributed delicate network light brown, thin network lines and its histologic correlation
Author(s) Oriol Yélamos · Katrin Kerl · Ralph P. Braun
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Status update July 24, 2019
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Pigment network consists of intersecting brown lines forming a grid-like reticular pattern (Kittler et al., 2016a). Histologically, the lines correspond to increased pigmentation (melanin within the keratinocytes or the melanocytes) along elongated rete ridgesEpidermal extensions that project into the underlying dermis (table 3). The “holes” of the network correspond to the suprapapillary plates (figure 2) (Massi et al., 2001b). The pigment network is usually absent in the faceis a central body region of sense and is also very central in the expression of emotion among humans and among numerous other species., palmsThis glossary term has not yet been described. and solesThis glossary term has not yet been described. and is replaced by a pseudo-networkstructureless brown interrupted by follicular openings (facial-skin) (face) and a parallel pigment pattern on acral skin (see below). The pigmented network can be described as typical or atypical.

Network schematic-42.jpg

Typical networkNetwork with minimal variability in the color thickness and spacing of the lines; symmetrically distributed

The typical or regular pigment network is characterized by uniform lines (in width and colorColor (American English) or colour (Commonwealth English) is the characteristic of human visual perception described through color categories, with names such as red, yellow, purple, or blue.) and is common in melanocyticThis glossary term has not yet been described. neviThis glossary term has not yet been described., but can be present in non-melanocytic lesions such as ink spot lentigoThis glossary term has not yet been described., dermatofibromas or accessory nipples (table 4) (Scope et al., 2006; Zaballos et al., 2008). Histologically, the brown lines of the typical networkNetwork with minimal variability in the color thickness and spacing of the lines; symmetrically distributed correspond to equidistant and uniform rete ridges. (Woltsche et al., 2017)

Network schematic.jpg

An example of a typical pigment network clinically and dermoscopically:

Reguler network.jpg

On histopathologyThis glossary term has not yet been described., the lines of the typical network correspond to pigment in the rete ridges, that are relatively uniform in width and equidistant from each otherThis glossary term has not yet been described..

Histology network.jpg

The typical network usually corresponds to the junctional component of a nevusThis glossary term has not yet been described.. However, reticulation can also be seen in darkly pigmented normal skin and in heavily pigmented rete ridges as encountered in dermatofibromas, ink spot lentigo or accessory nipples [1].

Atypical networkNetwork with increased variability in the color, thickness, and spacing of the lines of the network; asymmetrically distributed; gray color

Atypical pigment networkNetwork with increased variability in the color, thickness, and spacing of the lines of the network; asymmetrically distributed; gray color is irregularly meshed with lines varying in size, color, thickness or distribution and is often seen in dysplastic neviThis glossary term has not yet been described. and superficialThis glossary term has not yet been described. spreadingThis glossary term has not yet been described. melanomaThis glossary term has not yet been described. (Kittler et al., 2016a). On histopathology, the atypical pigment network corresponds to disarrangement of the rete ridges, tendency to confluence of nests of melanocytes and changes in melanin distribution within the epithelium (Russo et al., 2017). An atypical networkNetwork with increased variability in the color, thickness, and spacing of the lines of the network; asymmetrically distributed; gray color within a lesion may also appear perturbed and broken up, a finding referred to as “branched streaksBroadened or widened network with broken lines and incomplete connections”.

Atypical network31.jpg

An example of an atypical pigment network clinically and dermoscopically:

Atypical network.jpg

On histolopathology, the irregular lines of an atypical network correspond to variation in the width, length, and spacing of the rete ridges due to variation in the size, spacing, and tendency to confluence of melanocytic nests. Rete ridgesEpidermal extensions that project into the underlying dermis that are elongated and widened by larger junctional nests of melanocytes would appear as darker and wider lines on dermoscopy [2]. The atypical network is often seen in melanoma and dysplastic nevi [3] .

PseudonetworkA structureless pigment area interrupted by non-pigmented adnexal openings

The anatomyThis glossary term has not yet been described. of the rete ridgeThis glossary term has not yet been described. pattern of the face differs from that of non-facial skinThis glossary term has not yet been described., and is usually flatter. Accordingly, the pigment network is usually absent in these locations and is replaced by a pseudonetwork pattern. The "holes" in the pigmented epidermis correspond histologically to adnexal openings, such as sebaceous glands, hair follicles or sweat glands.

A pseudonetwork sketch:

Pseudonetwork schematic 23.jpg

Clinical and dermoscopic imagesA representation of a person, animal or thing, photographed, painted or otherwise made visible. of pseudonetwork:

Nevus face.jpg

Histologically, adnexal openings are responsible for the "holes" in the pigment reticulation:

Histology nevus face.jpg


ReferencesThis is material contained in a footnote or bibliography holding further information.
  1. Scope et al.: NonmelanocyticThis glossary term has not yet been described. lesions defying the two-step dermoscopy algorithmIn mathematics and computer science, an algorithm (Listeni/ˈælɡərɪðəm/ AL-gə-ri-dhəm) is a self-contained sequence of actions to be performed. Algorithms can perform calculation, data processing and automated reasoning tasks.. Dermatol Surg 2006;32:1398-406. PMID: 17083595. DOI.
  2. Russo et al.: DermoscopyThe examination of [skin lesions] with a 'dermatoscope'. This traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections. pathologyThis glossary term has not yet been described. correlation in melanoma. J. Dermatol. 2017;44:507-514. PMID: 28447355. DOI.
  3. Kittler et al.: Standardization of terminology in dermoscopy/dermatoscopyThe examination of [skin lesions] with a 'dermatoscope'. This traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections.: Results of the third consensus conference of the International Society of Dermoscopy. J. Am. Acad. Dermatol. 2016;74:1093-106. PMID: 26896294. DOI.