Solar lentigines / seborrheic keratoses / lichen planus-like keratosis (full text)

From dermoscopedia

Main PageNon melanocytic lesionsSolar lentigines / seborrheic keratoses / lichen planus-like keratosisSolar lentigines / seborrheic keratoses / lichen planus-like keratosis (full text)
0.00
(0 votes)

 Editor: Ralph P. Braun

 Author(s): Ralph P. Braun     ·  Stephanie Nouveau
Annotations
Description This chapter provides the full text of all previous chapters on 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. of Solar lentiginesThis glossary term has not yet been described. / seborrheic keratosesThis glossary term has not yet been described. / lichen planusThis glossary term has not yet been described.-like keratosis (full text)
Author(s) Ralph P. Braun · Stephanie Nouveau
Responsible author Ralph Braun→ send e-mail
Status released
Status update July 25, 2018
Status by Ralph P. Braun


User=
Solar lentigo schematic 2.jpg


Solar lentigoThis glossary term has not yet been described.

Solar lentigines are sharply circumscribed, uniformly pigmented macules that are located predominantly on the sun-exposed areas of the skinThis glossary term has not yet been described., such as the dorsum of the hands, the shoulders, and the scalp. Lentigines are a result of hyperplasia of keratinocytes and melanocytes, with increased accumulation of melanin in the keratinocytes. They are induced by ultraviolet light exposure.

Unlike freckles, solar lentiginesThis glossary term has not yet been described. persist indefinitely. Nearly 90% of Caucasians over the ageprocess of becoming older of 60 years have these lesions. Due to the increased prevalence of lentigines in the elderly, these lesions are sometimes referred to as “lentigo senilis”. However, younger individuals who tend to burn after ultraviolet exposure can also develop lentigines after acute or prolonged ultraviolet light exposure. Clinically, solar lentigines may be oval, round, or irregular in shape and can vary from a few millimeters to a few centimeters in diameter. Most lesions have a uniform light brown 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.; however, there are instances when they vary from dark brown to black. One variant of solar lentigoThis glossary term has not yet been described., “ink-spot” lentigo, has a jet-black color. Actinic purpura or other signs of solar damage can frequently be found in the skin surrounding solar lentigines. Solar lentigines are benignis any condition that is harmless in the long run lesions that can evolve to a pigmented seborrheic keratosisThis glossary term has not yet been described.. Histologically, it is characterized by club-shaped rete ridgesEpidermal extensions that project into the underlying dermis with small nub-like extensions. In addition, there is an increased number of melanocytes and increased pigmentation in the basal keratinocytes. Although most solar lentigines are easily recognized on clinical examinationThis glossary term has not yet been described., some lesions pose diagnostic challenges because their clinical appearance resembles that of melanomaThis glossary term has not yet been described.. 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. can be helpful in correctly differentiating a solar lentigo from melanoma. The key dermoscopic features of solar lentigines are as follows:

Moth-eaten borderThis glossary term has not yet been described.

The presence of a sharply demarcated and irregularly curved border is characteristic of solar lentigines. Often, portions of the border are scalloped, giving a motheaten appearance
Moth eaten.jpg

Homogenous light brown pigmentation

Many lesions have no structuresThis glossary term has not yet been described. or networks, only containing light brown and structureless areas; the term “jelly sign” had been proposed to describe the pigment quality of these lesions. The pigment appears as if jelly had been smeared on the skin surface.
Homogenous light pigmented SL.jpg

Pigment networkGrid-like pattern consisting of interconnecting pigmented lines surrounding hypopigmented holes.

There may be an area of faint, reticulation. This correlates with the presence of melanocytes and melanin-filled keratinocytes in the rete ridges.

A solar lentigo with pigment networkThis glossary term has not yet been described. and some finger print-like areas (see below)

Fingerprint-like areasThey are areas consisting of fi ne parallel running lines of light brown to dark brown colors. They resemble the dermatoglyphics of a human fingerprint.

They are areas consisting of fine parallel running lines of light brown to dark brown colorsThis glossary term has not yet been described.. They resemble the dermatoglyphics of a human fingerprint.

Untitled Artwork 24.jpg

PseudonetworkA structureless pigment area interrupted by non-pigmented adnexal openings

Lentigines located on the scalp and faceis a central body region of sense and is also very central in the expression of emotion among humans and among numerous other species. share features of pigmented melanocyticThis glossary term has not yet been described. lesions in this special location revealing a pseudonetworkA structureless pigment area interrupted by non-pigmented adnexal openings pattern. This is created when a diffusely pigmented area is interrupted by nonpigmented adnexal openings .

Symmetric brown follicular pigmentationThis glossary term has not yet been described.

In a solar lentigo the pigment around hair follicles is distributed in a symmetric fashion creating small brown circlesThis glossary term has not yet been described.. The pigment is usually light brown in color and similar to the color of the rest of the lesion. While the pigment is usually distributed symmetrically around the follicle, some follicles may appear asymmetrically pigmentedThis glossary term has not yet been described.. These asymmetrically pigmented follicles appear as brown crescent shaped structures. However, these asymmetric follicles will also have a brown color like the rest of the lesion. If the color of the pigment around the follicle, whether symmetric or asymmetric, is of a grayish hue or differs from the rest of the lesion then melanoma needs to enter the differential diagnosisis the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines with variations in the use of logic, analytics, and experience to determine "cause and effect". In systems engineering and computer science, it is typically used to determine the causes of symptoms, mitigations, and solutions.

Ink-sport lentigo

Ink-spot lentigines have their own distinct dermoscopic pattern.These lesions have a very prominent blackpigmented network, which has an almost three-dimensional quality under dermoscopy. The network lines can be either thin or thick in width, and the network ends abruptly at the edge of the lesion

Seb k schematic 2.jpg

Seborrheic keratosesThis glossary term has not yet been described.

Seborrheic keratoses are benign epithelial lesions that can appear on any part of the body except for the mucous membranes, palmsThis glossary term has not yet been described., and solesThis glossary term has not yet been described.. The lesions are quite prevalent in people older than 30 years. The etiology of seborrheic keratoses remains unclear. Ultraviolet light exposure may be responsible for the development of some seborrheic keratoses because they appear to evolve from solar lentigines; however, many develop in areas of the skin naturally protected from ultraviolet light exposure, such as the inframammary (intertriginous) areas. Clinically, early seborrheic keratoses are light- to dark brown oval macules with sharply demarcated borders (solar lentigo). As the lesions progress, they transform into plaques with a waxy or stuck-on appearance[1]. The surfaces of these lesions have a warty and keratotic appearance. Often, the lesions have follicular plugs scattered over their surfaces. The size of the lesions varies from a few millimeters to a few centimeters. Histologically, there are several distinct forms of seborrheic keratoses. In general, the lesions are characterized by papillomatous epidermal hyperplasia of uniform and monotonous keratinocytes and the presence of pseudocysts. The diagnosis of most seborrheic keratoses is straightforward. However, some seborrheic keratoses, especially the deeply pigmented variant, can simulate malignant melanomas. Thin, early lesions have moth-eaten borders and fingerprint-like structures as described for solar lentigines. Thicker pigmented seborrheic keratoses have the typical dermoscopy features as follows [2]:


Seb k schematic.jpg

Milia-like cystsThis glossary term has not yet been described.:

They are white-to-yellow, round structures that appear very bright when contrasted with their dark brown or black surroundings. The presence of multiple milia-like cystsThis glossary term has not yet been described. in pigmented seborrheic keratoses conjures up an image of “stars in the sky.” Milia-like cysts can also be seen in non-pigmentedThis glossary term has not yet been described. seborrheic keratosis and other lesions such as basal cell carcinomais the most common skin cancer, and one of the most common cancers in the United States.[1] While BCC has a very low metastatic risk, this tumor can cause significant disfigurement by invading surrounding tissues and melanocytic lesions including congenital neviis a type of melanocytic nevus (or mole) found in infants at birth. This type of birthmark occurs in an estimated 1% of infants worldwide; it is located in the area of the head and neck 15% of the time. and melanoma. However, if the lesion is non-melanocytic and is not a basal cell carcinoma then the presence of milia-like cyst is diagnostic of seborrheic keratoses specially if more then three are seen. It is interesting to note that the quality of milia-like cysts appear somewhat different in seborrheic keratosis and melanocytic lesions. In melanoma and congenital nevi the cysts appear “starry”, which is defined as small, bright and sharp. In seborrheic keratosis they appear “cloudy”, defined as larger and hazier in appearance. Histologically, the cysts correspond to intraepidermal, keratin-filled cysts. It is important to be aware that milia-like cysts are more conspicuous with non-polarized dermoscopy and are often difficultneeding much effort or skill to accomplish to visualize with polarized dermoscopy.
Milia like cysts.JPG

Comedo-like openings[[Comedo like openings]]:

They are round to ovoid craters that have black or brown comedo like plugs. Histologically, they correlate with keratin-filled invaginations of the skin surface.

Comedo like opening.JPG

Fissures and ridgeslines, curved and thick to describe the structural components of the pattern SK:

Fissures (sulci) are comedo-like openings[[Comedo like openings]], which are not round but rather linear and appear as dark brown to black linear to curvilinear structures within the lesion. The presence of numerous fissures and ridgeslines, curved and thick to describe the structural components of the pattern SK can result in the formation of network-like structuresThis glossary term has not yet been described. or result in a cerebriform patternIs a dermoscopy pattern that resembles the aspect of a brain. Commonly seen in seborrheic keratosis.. Histologically, they represent deep invaginations of the epidermis, filled with keratin.

Seb Ker sulci.jpg

Network-like structuresThis glossary term has not yet been described.:

Interlacing fissures and ridges can create an appearance of network-like structures. The quality of the grid of network-like structures in a seborrheic keratosis differs from the network grid seen in melanocytic neviThis glossary term has not yet been described. by being significantly larger. However, at times the network-like structure in a seborrheic keratosis can look very similar to that of a nevusThis glossary term has not yet been described.. Clinical examinationThis glossary term has not yet been described. of the lesion via side lighting can make the ridges more evident, thereby making it easier to differentiate network-like ridges in seborrheic keratosis and pigment network in melanocytic lesions.

Cerebriform patternIs a dermoscopy pattern that resembles the aspect of a brain. Commonly seen in seborrheic keratosis.:

Multiple fissures (sulci) and ridges (gyri) may produce a cerebriform pattern, where the structures resemble sulci and gyri of the brain (brain-like appearancelines, curved and thick to describe the pattern and fissures and ridges (former synonyms “gyry and sulci” and “fat fingers”) to describe the structural components of the pattern SK). These features are generally associated with an acanthotic seborrheic keratosis.

Fat-fingers:

Fat fingersthey are linear and wide dermoscopic structures corresponding to ridges. They often appear as short sausage-shaped structures. Colors of these structures vary from tan/brown, blue and can be hypopigmented. are linear and wide dermoscopic structuresThis glossary term has not yet been described. corresponding to ridges. They often appear as short sausage-shaped structures. Their colors vary from tan/brown, blue to hypopigmentedThis glossary term has not yet been described.. They are named fat-fingers because their shapes can resemble a straight finger (linear), bent finger (curvi-linear), or finger tip (oval–circular).
Seb Ker Fat Fingers.jpg

Sharply demarcated borders:

As known from clinical examination, seborrheic keratosis often have sharply demarcated borders.

Typical hairpin blood vesselsThis glossary term has not yet been described. :

Some seborrheic keratoses are associated with hairpin vesselsThis glossary term has not yet been described.. These hairpin vessels can appear as perfect “U”-shaped vessels of as “U”-shaped vessels that are twisted upon themselves. Typical hairpin blood vessels have a whitish halo around the blood vessel corresponding to the surrounding keratin. It is important to note that some melanomas can have hairpin vessels, but these vessels generally do not have the surrounding white halo but rather have a pink halo. Similar hairpin vessels on a pink background can be seen in irritated seborrheic keratosis.

Wobble testThis glossary term has not yet been described.:

This is a dynamic test that can only be performed with a contact dermoscopy deviceA piece of equipment designed to perform a special function. The test is performed as follows: once the contact plate of the dermoscope is firmly pressed down (pressure in vertical direction) against the lesion, it is then moved slightly back and forth in the horizontal plane (parallel to the skin surface). Seborrheic keratosisThis glossary term has not yet been described. will appear to stick to the glass plate and move en bloc with the movement of the dermoscopic face plate. In other words, they will slide back and forth. In contrast, nevi will not move en bloc but, rather roll back and forth. In other words, intradermal neviThis glossary term has not yet been described. will wobble. Knowledge of the above-described dermoscopic features and patternsThis glossary term has not yet been described. seen in seborrheic keratosis will often prove valuable in differentiating seborrheic keratoses from other lesions, including melanoma. However, irritated or traumatized seborrheic keratoses can mimic melanoma or squamous cell carcinomaThis glossary term has not yet been described.. In these cases the history of traumaThis glossary term has not yet been described. or the presence of typical criteriameasure of how well one variable or set of variables predicts an outcome for seborrheic keratoses in another part of the lesion might be comforting. However, it is important to remember that skin cancerThis glossary term has not yet been described. can develop within a seborrheic keratosis, and thus a biopsy is justified for atypical appearing seborrheic keratosis.


Lichen Planus-like Keratosis

Introduction

Lichen planusThis glossary term has not yet been described.-like keratosis, also known as LPLKLichen planus like keratosis and lichenoid keratosis, is one of the common benign neoplasms of the skin. It is believed to be either a seborrheic keratosis or a solar lentigo that is undergoing regressionThis glossary term has not yet been described.. Supporting evidence has been published beginning with Mehregan’s findings of the presence of lentiginous epidermal hyperplasia in lesions interpreted as LPLK[3]. Further supporting evidence can be found by Laur, et al who in 1981 published a detailed clinical-histopathologic correlation in the JAAD [4]. In addition, Goldenhersh et al [5], described performing biopsies of lentigines on two instances. The first being a biopsy of a solar lentigo and 5 years later, after the lesion had demonstrated a clinical change into a solitary lichen planus‐like keratosis.

Clinical and Histologic Appearance

Lichen planus-like keratosis is a great masquerader with a differential diagnosis including basal cell carcinoma, squamous cell carcinoma and melanoma. The wide differential diagnosis is due to the extreme variability in characteristic appearance with many pigmentation and morphologic possibilities. The clinical appearance depends on its stage of evolutionis change in the heritable characteristics of biological populations over successive generations.

The lesion can appear as a macule or papule that is pink, pinkish brown, pinkish orange, rust colored, purplish brown, dusky violaceous or blue-gray to black. Some lesions are characterized by a velvety appearance, some have a fine scale, while othersThis glossary term has not yet been described.This glossary term has not yet been described. have accentuated skin markings. Lesions can be solitary or in some cases multiple.


Early Stage

The histologic features of early stage of LPLK include hypergranulosis, epidermal hyperplasia, a few necrotic keratinocytes and a superficialThis glossary term has not yet been described., bandlike lichenoid infiltrate. Clinically these lesions appear as pink macules or papules and may be difficult to distinguish from basal cell carcinoma or squamous cell carcinoma.


Intermediate Stage

Histologically intermediate stage LPLK is characterized by melanophages, inflammatory cells and fibrosis, with features consistent with either a lentigo or a seborrheic keratosis. In some cases, clinically, the lesion may be difficult to distinguish from melanoma (melanoma on sun-damaged skin, lentiginous melanoma, lentigo maligna melanomaThis glossary term has not yet been described.).


Late Stage

Late stage LPLK is characterized histologically by papillary fibrosis, telangiectasias, and melanophages. The lesions have a more blue-gray to black clinical appearance and may be difficult to distinguish from melanoma.

Dermatoscopic Criteriameasure of how well one variable or set of variables predicts an outcome

Dermoscopy allows the detailed visualization of the structures found within the epidermis, dermoepidermal junction and papillary dermis. This information creates a bridge between the clinical and histologic correlates, thus narrowing the differential and allowing for a more accurate assessment of the lesion.


Early Stage LPLK

Lichen planus-like keratosis in its early stage is characterized by polymorphous vesselsmultiple types of vessels are present may indicate malignancy in appropriate context for example in flat melanocytic lesions: dotted vesselstiny pinpoint vessels and short thin vessels that are either linear, slightly curved or serpentine in appearance. The lesions may appear structurelessThis glossary term has not yet been described., pink-white with an orange or yellow hue, colors that are not bright nor saturated, borders that are scalloped and a scale. Shiny white structuresThis glossary term has not yet been described. (SWS, or crystalline structures) are commonly seen with LPLK, that appear as white strands or blotches. RosettesFour bright white dots or clods arranged together as a square (or a four leaf clover) can also be seen with LPLKs that coincide with actinically damaged skin.

Here are two examples of early stage LPLKs:

Early stage lplk 2.jpg
Early stage LPLK.jpg

Intermediate Stage LPL

Lichen planus-like keratosis in the intermediate phase is characterized by two patterns. The first pattern depicts the dermoscopic features of a solar lentigo (fine lines parallel; straight, slightly curved, long or short, with sharply demarcated and scalloped borders) with the addition of regression structuresThis glossary term has not yet been described.: focal gray dotsDots are small, round structures of less than 0.1 mm in diameter that have a red color when corresponding to blood vessels; however, when due to melanin, their color ranges from black, brown, to blue-gray depending on the depth and concentration of the melanin in the skin (Tyndall effect)./granules.

INTERMEDIATE lplk sl.jpg

The second pattern portrays the features of a seborrheic keratosis (borders sharply demarcated, milia-like cysts, comedo-like openings, fissures, ridges, looped vesselsmetaphoric term: hairpin vessels <br /> two parallel linear vessels forming a half looped or hairpin like structure <br />

seen in seborrheic keratosis viral warts and fine vessels surrounded by a halo) with the addition of regression structures: focal gray dots/granules.

Intermediate LPLK SK.jpg

Late Stage LPLK

Lichen planus-like keratosis in the late phase is characterized by scattered clumps of pigment with diffuse gray dots/granules or gray dots/granules that form what is known as a diffuse granular pattern, and borders that are often scalloped or have a moth-eaten appearance.

Late stage LPLK3.jpg

Differential diagnosis

In a recent study for the US [6] LPLKs were compared with non-LPLK cutaneous lesions. LPLKs had the clinical differential diagnosis of basal cell carcinoma, squamous cell carcinoma, neavus, melanoma, seborrehic keratosis, lentigo, and actinic keratosisActinic keratosis (also called solar keratosis and senile keratosis; abbreviated as AK) is a pre-cancerous patch of thick, scaly, or crusty skin.. Dermoscopic features that were found to distinguish LPLKs from other lesions include: Overall organized dermoscopic structures, scale, orange color, coarse +/- fine granules and peppering as the only feature present. LPLKs were less likely to have moth-eaten borders and irregular dotsAny distribution of dots other than dots as described for regular dots. compared to the other lesions.



ReferencesThis is material contained in a footnote or bibliography holding further information.:
  1. An Atlas of Dermoscopy, Second Edition. Marghoob A. et al. CRC Press; 2012.
  2. Braun et al.: Dermoscopy of pigmented seborrheic keratosis: a morphological study. Arch Dermatol 2002;138:1556-60. PMID: 12472342.
  3. Mehregan &: Lentigo senilis and its evolutions. J. Invest. Dermatol. 1975;65:429-33. PMID: 127813.
  4. Laur et al.: Lichen planus-like keratosis. A clinicohistopathologic correlation. J. Am. Acad. Dermatol. 1981;4:329-36. PMID: 7217401.
  5. Goldenhersh et al.: Documented evolution of a solar lentigo into a solitary lichen planus-like keratosis. J. Cutan. Pathol. 1986;13:308-11. PMID: 3771875.
  6. Liopyris et al.: Clinical and dermoscopic features associated with lichen planus-like keratoses that undergo skin biopsy: A single-center, observational study. Australas. J. Dermatol. 2018;. PMID: 30450536. DOI.