Lichen planus-like keratosis
|Description||In this chapter we describe the dermoscopyDermoscopy is a non invasive diagnostic method. of lichen planus like keratosisThis glossary term has not yet been described.|
|Author(s)||Maggie Oliviero · Harold Rabinovitz|
|Owner||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 LPLK and lichenoid keratosis, is one of the common benignThis glossary term has not yet been described. 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 (1). Further supporting evidence can be found by Laur, et al who in 1981 published a detailed clinical-histopathologic correlation in the JAAD (2). 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.
Clinical and Histologic Appearance
Lichen planus-like keratosis is a great masquerader with a differential diagnosisThis glossary term has not yet been described. 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 evolutionThis glossary term has not yet been described..
The lesion can appear as a macule or papule that is pink, pinkish brown, pinkish orange, rust colored, purplish brown, dusky violaceous, blue-gray to black. Some lesions are characterized by a velvety appearance, some have a fine scale, while others have accentuated skin markings. Lesions can be solitary or in some cases multiple (2) (Figure1A&B). Figure 1B: LPLK on the forearm demonstrates an area of inflammation within a solar lentigo. The process is consistent with an active area of early regression, evident by the inflamed pink area.
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 difficultThis glossary term has not yet been described. 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.
DermoscopyDermoscopy is a non invasive diagnostic method. 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: short thin vesselsThis glossary term has not yet been described. that are either linear, slightly curved or serpentine in appearance, and vessels depicted as focal red dotsThis glossary term has not yet been described.. The lesions may appear structureless, pink-white with an orange or yellow hue, colors that are not bright nor saturated, borders that are scalloped and a scale (Figure 2). Shiny white structures (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 (Figure 3A & B).
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 structures: focal gray dots/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.