Chapter 30:: Parapsoriasis (and Pityriasis Lichenoides)
:: Stefan M. Schieke & Gary S. Wood
鄭煜彬(20200111)
What entities are included in
parapsoriasis?
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Large plaque parapsoriasis, small plaque
parapsoriasis, & pityriasis lichenoids(PLEVA & PLC)
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What is Mucha-Habermann disease?
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Pityriasis
lichenoides et varioliformis acuta(PLEVA)
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PARAPSORIASIS
EPIDEMIOLOGY
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What is the range and peak of age in parapsoriasis?
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Middle-aged to older, fifth decade
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How much is the male-to-female ratio of SPP
& LPP?
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SPP: 3:1
LPP: 1~: 1(M>F)
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CLINICAL FEATURES
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What is the clinical classification of
SPP/LPP/PL?
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Papulosquamous lesions: papules with scales
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What is the symptoms of LPP?
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Asymptomatic or mildly pruritic.
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What is the morphology of LPP?
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Variable-sized(>5cm), light red-brown
or salmon pink, oval or irregularly shaped, well-marginated patches or very thin plaques with small and scanty scales.
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What is the location of LPP?
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“Bathing trunk(esp. breasts of women)”
and flexural areas, as MF
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What material is used to describe to the
fine wrinkle & epidermal atrophy of LPP?
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Cigarette paper
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What is the triad of poikiloderma?
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Telangiectasia, mottled pigmentation,
& atrophy.
(=poikiloderma atrophicans vasculare)
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What is the only variant of LPP?
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Retiform parapsoriasis: scaly macules
& papules in a net-like or zebra-stripe pattern
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What is chronic superficial dermatitis?
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Small plaque parapsoriasis
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What is the morphology of SPP?
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<5cm, round or oval discrete patches or very thin plaques with fine, moderately adherent scales.
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What is the location of SPP?
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Trunk
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What is two variants of SPP?
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1.
digitate dermatosis
2.
hypopigmented SPP
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What is the morphology of digitate
dermatosis?
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A finger shape, yellowish or fawn-colored(淺黃褐色) lesions along the lines of cleavage. The long axis> 5cm.
(xanthoerythrodermia perstans)
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What is the common complications of
parapsoriasis(4)?
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1.
impetiginization secondary to
excoriation
2.
mycosis fungoides
3.
Cardio/Cerebro-Vascular
Diseases
4.
Hematologic &
nonhematologic malignancies
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ETIOLOGY & PATHOGENESIS
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Which two diseases are bridged by parapsoriasis?
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Chronic dermatitis & mycosis
fungoides (MF)
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What is the abnormal tissue of
parapsoriasis or MF?
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Skin-associated lymphoid tissue (SALT): T
cells express cutaneous lymphocyte-associated antigen
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Where does SALT locate?
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Skin, peripheral lymph nodes, lymphatics &
blood-stream.(T-cells in the circuit, not a tissue)
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Why are MF, parapsoriasis & chronic
dermatitis so difficult to distinguished?
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All continue to traffic and participate
in delayed-type hypersensitivity reactions to contact allergens after
neoplastic transformation.
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Please describe the relationship of LPP
to MF.
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The clinically benign end of the MF
disease spectrum: they are monoclonal disorders with different dominant
T-cell clonal density
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What is the major factor to decide the
clinical difference between parapsoriasis & MF?
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Genetic and/or epigenetic differences(the
more mutations, the more malignant)
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How to name the chronic spongiotic dermatitis
which may progress to MF?
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Clonal dermatitis
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Please draw a sketch of the relation
between follicular mucinosis(FM); large-plaque parapsoriasis(LPP);
nonspecific chronic spongiotic dermatitis(NCSD);
primary erythroderma(PE); & clonal
dermatitis?
|
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What is the difference between the clonal
dermatitis & MF?
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Clonal
dermatitis is polyclonal; MF is monoclonal.
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Which virus may induce MF?
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HHV-8
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DIAGNOSIS
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What is the clinical difference between
LPP & SPP?
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LPP has larger size, asymmetric distribution, irregular shape, less
discrete lesions, & poikilodermatous appearance.
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What is the difference between LPP &
patch stage of MF?
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No
diffenrence(indistinguishable)
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What is the main difference between
parapsoriasis & MF?
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Parapsoriasis has no induration or palpable infiltration
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What is the criteria to diagnose MF?
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Since LPP& MF are indistinguishable,
why should we use the name LPP?
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1.
It guides treatment and
followup as MF
2.
The risk of dying from
lymphoma(MF) is small.
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What is the major difference between SPP
& MF?
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MF had poikiloderma, moderate to thick
plaques.
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PATHOLOGY
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What can you see in the slide of early
SPP?(Please answer according to epidermis & dermis)
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E: mild spongiosis + focal hyperkeratosis,
parakeratosis(scale), crust, & exocytosis.
D: mild superficial perivascular
lymphohistiocytic infiltrate + edema
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What can you see in the slide of late
SPP?
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As early SPP (no progression)
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What can you see in the slide of early LPP?
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E: mildly acanthotic & hyperkeratotic
epidermis + spotty parakeratosis.
D: Perivascular & scattered dermal
lymphocytic infiltrate
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What can you see in the slide of advanced
LPP or MF?
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An interface infiltrate + mild spongiosis
+ epidermotropism (scattered singly or in groups).
Poikiloderma: atrophic epidermis, dilated
blood vessels, & melanophage
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What are the different immunohistologic
features between SPP & LPP/early MF?
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(CD4+ T-cells predominate in these
dermatitides) LPP/MF has CD7 deficiency, epidermal expression of HLD-DR.
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DIFFERENTIAL DIAGNOSIS
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What is the difference between SPP/LPP/MF
& psoriasis?
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Psoriasis has Auspitz sign, micaceous
scale, nail
pits, & lesions on the scalp, elbows,
& knees.
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CLINICAL COURSE AND PROGNOSIS
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How many percent of cases of LPP &
SPP become MF in the future?
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LPP: 10% to 30%
SPP: 0%
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Which variant of LPP usually progress to
MF?
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The retiform variant
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MANAGEMENT
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How to treat SPP?
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Emollients, topical tarcortic/osteroids,
& BBUVB
F/u every 3-6 months.
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How to treat LPP?
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Topical: strong corticosteroids, nitrogen
mustard
Phototherapy: BB/NBUVB, UVA1, PUVA, excimer
F/u every 3-6 months.
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How to treat MF?
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Phototherapy: BBUVB, NBUVB, UVA1, PUVA
Topical: nitrogen mustard, bexarotene
gel, imiquimod, carmustine (BCNU).
Electron-beam radiation
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