Structureless areas (full text)

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Main PageHistopathological correlationStructureless areas (full text)
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 Authored by: Ralph P. Braun     ·  Katrin Kerl

 Keywords:   structureless area · histology · histopathology · nevus · melanoma · blotch · regular blotch · irregular blotch
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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
Responsible author Ralph Braun→ send e-mail
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Status update July 27, 2017
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Areas within a lesion that are devoid of any networkThis glossary term has not yet been described. or other structuresThis glossary term has not yet been described., such as globules or regression structuresThis glossary term has not yet been described., are called “structureless areas.” Structureless areas are defined as areas with a size that is at least 10% of the lesion’s surface area and are devoid of any discernible structures, such as globulesThis glossary term has not yet been described., network, or regression structures (i.e., scars, pepperingGray dots, granularityThis glossary term has not yet been described., or blue-white veil over fl at areas).


Structureless areas hypopigmentedThis glossary term has not yet been described.

They are hypopigmented 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.. However, 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 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 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).

Peripheral reticuler central hypopigmentation schematic.jpg


Nevus central hypopigmentation.jpg

Structureless areas, hyperpigmented (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 pigmentedThis glossary term has not yet been described.. 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. The dark pigment in a blotch visually obscures the ability to discern any underlying structures. 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 network often surrounds a regular blotchOne blotch within center of lesion and surrounded by network. Regular blotches are associated with nevi.

Regular blotch 29.jpg

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

Regular blotch.jpg


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.
Atypical blotch 37.jpg


Irregular blotch.jpg


Irregular blotch histopathology.jpg