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ERYTHEMA DYSCHROMICUM PERSTANS (tier 2)
Some lichenoid reactions, if sampled late in the evolution of a lesion, or if, by nature, indolent processes, are cell-poor at the dermal-epidermal interface; they show only focal,
mild vacuolar changes at the dermal-epidermal interface. Such lesions qualify as senescent lichenoid reactions. In addition, many of these variants are associated with melanoderma; such lesions qualify as pigmented,
senescent lichenoid reactions. They also would qualify as pigmented poikilodermas. The list would include erythema dyschromicum perstans, poikiloderma of Civatte, berloque dermatitis, and even senescent drug
reactions (S5C19VA2-4).
The reaction in erythema dyschromicum perstans is a spotty, cell-poor lichenoid reaction with changes often most prominent at the tips of rete ridges
(S5C21P14-1-7, & S5C23P16-1 & 2). In some
examples, lytic defects containing colloid bodies are a prominent feature (a feature that would qualify as a focal, mild lichen planus-like reaction). Melanoderma varies in intensity (S5C22P15-1-3).
THE LICHENOID REACTION OF LS&A
The lichenoid reaction of LS&A is prominent in young lesions; it is variably represented in old lesions. In young lesions, lytic defects may be found at the D-E interface (a lichen
planus-like feature). In some early lesions, hyalinization begins at the D-E interface; this relationship suggests that the collagen of the hyalin may share features with components of the basement membrane (S5C23P16-3-5).
The patterns of radiodermatitis qualify as a senescent lichenoid reaction. Often, the D-E interface is straight, and shows vacuolar changes (S5C23P16-6). The upper portion of the dermis shows atrophy, edema and fibrosis; elastotic changes are common. Telangiectasia is
usually a feature; it may be associated with areas of fibrinoid degeneration. Some vessels show thickened walls with subendothelial collections of xanthoma cells. In the fibrotic dermis, some of the fibroblasts are
stellate in outline and have enlarged, hyperchromatic nuclei. In old lesions, skin appendages often are atrophic. The reaction in the upper portion of the dermis may be mistaken for that of LS&A. Also in old
lesions, varying degrees of keratinocytic dysplasia, often of a hyperplastic type, may be a feature.
Ruzicka T, et al: Annular erythema associated with Sjorgren’s syndrome: a variant of systemic lupus erythematosus. J Am Acad Dermatol 1991;25: 557-60.
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