Lichen planus-like keratosis
|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. of lichen planus like keratosisThis glossary term has not yet been described.|
|Author(s)||Maggie Oliviero · Harold Rabinovitz|
|Responsible author||Maggie Oliviero → send e-mail|
|Status update||May 29, 2017|
|Status by||Ralph P. Braun|
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 skinThis glossary term has not yet been described.. It is believed to be either a seborrheic keratosisThis glossary term has not yet been described. or a solar lentigoThis glossary term has not yet been described. 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. Further supporting evidence can be found by Laur, et al who in 1981 published a detailed clinical-histopathologic correlation in the JAAD . In addition, Goldenhersh et al , 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 planusThis glossary term has not yet been described.‐like keratosis.
Clinical and Histologic Appearance
Lichen planus-like keratosis is a great masquerader with a 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 including basal cell carcinomais the most common skin cancer, and one of the most common cancers in the United States. While BCC has a very low metastatic risk, this tumor can cause significant disfigurement by invading surrounding tissues, squamous cell carcinomaThis glossary term has not yet been described. and melanomaThis glossary term has not yet been described.. 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.
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 difficultneeding much effort or skill to accomplish to distinguish from basal cell carcinoma or squamous cell carcinoma.
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 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.
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. allows the detailed visualization of the structuresThis glossary term has not yet been described. 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 vesselsThis glossary term has not yet been described. 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, colorsThis glossary term has not yet been described. 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:
Intermediate Stage LPLLichen planus-like keratosis in the intermediate phase is characterized by two patternsThis glossary term has not yet been described.. 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.
The second pattern portrays the features of a seborrheic keratosis (borders sharply demarcated, milia-like cystsThis glossary term has not yet been described., comedo-like openings[[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.
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.
In a recent study for the US  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, lentigoThis glossary term has not yet been described., 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 structuresThis glossary term has not yet been described., scale, orange 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., 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.:
- Mehregan: Lentigo senilis and its evolutions. J. Invest. Dermatol. 1975;65:429-33. PMID: 127813.
- Laur et al.: Lichen planus-like keratosis. A clinicohistopathologic correlation. J. Am. Acad. Dermatol. 1981;4:329-36. PMID: 7217401.
- 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.
- 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.