Paraopsoriasis, PLEVA, PRP Flashcards
Pathogenesis of small plaque parapsoriasis
Pathogenesis
•Etiology = largely unknown
•Superficial skin lymphoid infiltrate – composed mostly of CD4+ T cells
•Dominant T-cell clonality has been demonstrated in some cases
•clonal dermatitis transitional step between chronic dermatitis and overt CTCL. (“clonal dermatitis”, which also includes large plaque parapsoriasis, have an ~20% risk of progression to overt CTCL over 5 years)
Clinical features of small plaque parapsoriasis
•Patches rather than plaques in both small and large plaque parapsoriasis (despite name)
•Chronic + asymptomatic (may be mildly pruritic)
•Wax and wane early – can progress. Can regress (spontaneously/after rx -may take years)
•Round–oval patches <5 cm in diameter
•May be widespread on trunk/extremities – or limited (if limited usually sun exposed)
•Erythema variable but less than psoriasis
•Yellow hue - “xanthoerythrodermia perstans”
•Variant “digitate dermatosis” = elongated, finger-like patches symmetrically distributed on the flank These (exception to the 5-cm rule - may measure 10 cm or more in long axis)
•Risk of progression to mycosis fungoides: zero to low
Pathology of small plaque parapsoriasis
•Mild, non-specific, spongiotic dermatitis with focal parakeratosis
•Exocytosis of lymphocytes usually present
Treatment of small plaque parapsoriasis
Treatment
•Reassure – risk for MF low
•Can be monitored without treatment
•Topical corticosteroids, topical coal tar, phototherapy
•Role of Imiquimod , topical calcineurin inhibitors needs to be established (concern that topical calcineurin inhibitors may be implicated in the development of lymphoma therefor CAUTION RECOMMENDED)
Pathogenesis of large plaque parapsoriasis
Pathogenesis
•Etiology = largely unknown
•Superficial skin lymphoid infiltrate – composed mostly of CD4+ T cells
•Dominant T-cell clonality has been demonstrated in many cases
•Well established that some cases of large plaque parapsoriasis represent patch stage of Mycosis Fungoides
•Progression of large plaque parapsoriasis to more overt forms of lymphoma at a rate of 10% to 35% over a period of 6–10 years
Clinical features of large plaque parapsoriasis
Pathology of large plaque parapsoriasis
1) Parakeratosis, non-specific spongiotic dermatitis/interface lymphocytic infiltrate
2) Some can resemble patch stage of mycosis fungoides (atypical lymphoid cells)
3) may need repeat biopsies
4) Poikilodermatous variants of large plaque psoriasis – can show histopathological triad epidermal atrophy, telangiectasis, pigment incontinence
Treatment of large plaque parapsoriasis
1) should be treated regardless if represent Mycosis Fungoides/may evolve into mycosis fungoides
2) Same as for small plaque psoriasis
3) If criteria for MF met – treat accordingly
Differential diagnosis of small and large plaque parapsoriasis
Therapeutic ladder for small and large plaque parapsoriasis.
Pathogenesis of PLEVA
- associated with
1) infections (eg HIV, parvovirus B19)
2) medications (estrogen-progesterone, TNF alpha inhibitors – infliximab, radiocontrast)
3) possible host (child) versus graft (mom) disease
4) Both PLEVA and PLC – lesional T-cell infiltrates
•CD8+ predominance in PLEVA
•CD4+ predominance in PLC
5) Both lesions can demonstrate dominant T-cell clonality but more easily seen in PLEVA (infiltrate denser) - indicates that that it is T-cell lymphoproliferative disorder, occasional association with cutaneous T-cell lymphoma, Hodgkin’s disease and other lymphomas
Clinical features of pleva/PLC
1) Crops of spontaneously regressing erythematous to purpuric papules
•Acute = PLEVA
•Chronic =PLC
2) May have mixed forms (serially or concurrently)
3) PLEVA – individual lesions develop crust/ulcers + occasionally vesicles/pustules - varioliform scars if extensive
4) Usually asymptomatic and resolve within weeks
5) Usually confined to skin (rare cases - associated with malaise, fever, lymphadenopathy, arthritis, bacteremia)
6) febrile ulceronecrotic Mucha–Habermann disease (FUMHD) - severe variants in (large, confluent necrotic skin lesions as well as mucosal, gastro- intestinal, and pulmonary involvement) - associated with increased serum levels of TNF-α
Describe the clinical features of plc
•PLC – lesions erythematous to red-brown and scaly – indolent course-> regress over weeks to months (if resolve – can leave hypopigmented macules)
•Resolve spontaneously or follow chronic relapsing course – (distribution more important than acute/chronic in outcome)
•Diffuse distribution – shortest course. Peripheral distribution – longest course. Central = intermediate course
Pathology of PLEVA/PLC
Superficial perivascular interface dermatitis in all cases
•Acute spectrum = denser infiltrate (top heavy, wedge shaped)
•Lymphocytes predominate (can be mixed with neutrophils)
•Epidermis- focal parakeratosis (edema to epidermal necrosis in well developed lesions)
•Extravasation of erythrocytes
•Crusts, vesiculopustules, ulcers
•Lymphocytic vasculitis BUT true fibrinoid necrosis of blood vessles NOT seen
•changes are blunted in chronic lesions
•Lymphoid atypia NOT a standard feature
•Some pathologists allow occasional atypical lymphocytes, others regard this as a signof lymphomatoid papulosis or another form of CTCL
Treatment of PLC/PLEVA
•If drugs suspected – trial of discontinuation of suspected drug
•First line – topical c/s, topical coal tar, tetracyclines/erythromycin (children) – for anti-inflammatory effect with sevral month course needed and gradual tapering, phototherapy.
Oral Abx if secondary infection (usually Staph Aureus)
•Fulminant cases – low dose weekly MTX
•If associated with fever, arthritis – systemic corticosteroids, IVIg or cyclosporine (once infection excluded)
•Anti-histamines if pruritic
•Reports of efficacy with TNF alpha inhibitors, oral bromelin, photodynamic therapy
Differential diagnosis of PLEVA
Therapeutic ladder for PLC/PLEVA
Types of pityriasis rubra pilaris
Pathogenesis of pityriasis rubra pilaris
Pathology of PRP
Treatment of PRP
Clinical features of PRP
1) Small groups of follicular hyperkeratotic papules may be noted on the dorsal fingers or the head and neck. “nutmeg grater”
2) progress in a cephalocaudal manner.
Involved skin is often sharply demarcated from adjacent uninvolved skin - “islands of sparing.”
3) The disease often progresses into diffuse erythroderma
4) The epidermal scale is fine and nonadherent, termed pityriasiform or furfuraceous
5) In deeply pigmented skin, the characteristics lesions of PRP appear hyperpigmented with subtle dark red to violaceous In lightly pigmented skin, the lesions are pink-red to salmon-coloured
6) Palmoplantar keratoderma (PPK) is another characteristic finding in PRP and classically has a unique waxy red-orange or bright yellow color.
7) Nail involvement is common, with subungual hyperkeratosis, splinter hemorrhages, and longitudinal ridging.
8) Eruptive seborrheic keratoses are occasionally found in erythrodermic PRP; these have not been associated with malignancy
9) During the resolution phase of PRP, cutaneous plaques may form an erythema gyratum repens-like morphology, with parallel arcuate rings resembling wood grain.
This likewise has not been associated with malignancy when it occurs in association with PRP, as compared with true erythema gyratum repens, which often is a sign of underlying malignancy.
