Structureless areas (full text)

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Main PageHistopathological correlationStructureless areas (full text)
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 Author(s): Ralph P. Braun     ·  Katrin Kerl
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Description In this chapter 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. term structureless areas and their histopathological correlation including regular blotches, irregular blotches
Author(s) Ralph P. Braun · Katrin Kerl
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Areas within a lesion that are devoid of any network or other structuresThis glossary term has not yet been described., such as globules or regression structures (i.e., scars, pepperingGray dots, granularityThis glossary term has not yet been described., or blue-white veil over flat areas), are called “structureless areas”. Their size should be at least 10% of the lesions's total surface area. Structureless areas can be hypopigmentedThis glossary term has not yet been described., hyperpigmented or regularly pigmentedThis glossary term has not yet been described..

Hypopigmented structureless areas

Hypopigmented structureless areas have a lighter pigment compared with the rest of the lesion; however, they manifest the same or slightly more pigment compared with the surrounding normal skin (N.B.: structureless areas that are hyperpigmented are called blotches). Focal structureless areas within a lesion are a common finding in neviThis glossary term has not yet been described..

Nevus central hypopigmentation.jpg
In contrast, focal tan to light brown structureless areas at the periphery of a melanocyticThis glossary term has not yet been described. lesion is commonly associated with melanomaThis glossary term has not yet been described.. Peripherally located structureless areas in melanoma tend to have a light brown to fawn color and tend to end abruptly at the edge of a lesion. Histologically, these areas are characterized by flattening of the DEJ (loss of the undulating pattern of rete ridgesEpidermal extensions that project into the underlying dermis and dermal papillae) and scattering of atypical melanocytes in suprabasal epidermal layers (i.e., pagetoid cells).

MelanomaThis glossary term has not yet been described. displaying tan structuresless area

Hyperpigmented structureless areas (Blotches)

A blotchDark structureless areas is defined as an area with a size that is at least 10% of the lesion’s surface area and is heavily pigmented. In a blotch the melanin pigment is often present throughout the skinThis glossary term has not yet been described., including the stratum corneum, epidermis, and the dermis [1]. The dark pigment in a blotch visually obscures the ability to discern any underlying structures [2]. Blotches can be regular or irregular.

Regular hyperpigmented structureless areaThis glossary term has not yet been described. (BlotchDark structureless areas)

Peripheral reticuler central hyperpigmentation schematic.jpg

Regular blotches are defined as those that display symmetry, regular borders,homogenous dark hue, and are located within the center of the lesion. A pigment networkThis glossary term has not yet been described. often surrounds a regular blotchOne blotch within center of lesion and surrounded by network. Regular blotches are associated with nevi.

Regular blotch.jpg

Regular blotches can be seen in “activated” nevi and are attributed to heavy melanin concentrations in the stratum corneum. Because the pigment is concentrated in the stratum corneum, it can easily be stripped off using a tape-stripping procedure, thereby revealing underlying structures.


Irregular hyperpigmented structureless areablotch If centric hypermelanotic Clark (“dysplastic”) nevus if eccentric melanoma (Blotch)

Irregular blotches are defined as those that are asymmetric, have irregular contours, are located off center, and/or display multiple dark hues (i.e., heterogenous dark hues). Irregular blotches are associated with melanoma or dysplastic nevusThis glossary term has not yet been described..

Atypical blotch 37.jpg
Irregular blotch.jpg
Irregular blotch histopathology.jpg


ReferencesThis is material contained in a footnote or bibliography holding further information.
  1. Yadav et al.: Histopathologic correlates of structures seen on dermoscopy (epiluminescence microscopy). Am J Dermatopathol 1993;15:297-305. PMID: 8214386.
  2. 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 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.. J. Am. Acad. Dermatol. 2016;74:1093-106. PMID: 26896294. DOI.