Pityriasis Lichenoides et Varioliformis
Acuta (PLEVA)
Pityriasis Lichenoides Chronica
Epidemiology:
Common sites:
Gross features:
- PLEVA:
- sudden onset
- crops of small,
ulcerated papules
- may heal with
superficial scarring (varioliform)
- PLC:
- Red-brown
papules
- Characteristic
“wafer-like” scale
Histologic features:
- PLEVA:
- Early:
- Marked vacuolar
interface change (intracytoplasmic vacuoles
in basal keratinocytes)
- Broad zone of
full-thickness epidermal necrosis
- Parakeratosis overlying zone of necrosis
- Neutrophils in the stratum corneum
- lymphycyte exocytosis
- spongiosis
- erythrocyte extravasation into epidermis
- dense, wedge-shaped
dermal lymphocytic infiltrate (base of wedge
at epidermis)
- large
transformed lymphocytes present
- perivascular hemorrhage
- PLC:
- Similar but less
destructive
- Parakeratosis – well-developed, sharply
demarcated
- Vacuolar interface
change (less than PLEVA)
- Lymphocyte exocytosis (less than PLEVA)
- Wedge-shaped
dermal lymphocytic infiltrate
Immunophenotype:
Marker:
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Sensitivity:
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Specificity:
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Molecular features:
Other features:
References: