Pemphigus Vulgaris (PV) Histopathology
Pemphigus Vulgaris is a life-threatening autoimmune blistering disorder characterized by the loss of cell-to-cell adhesion (acantholysis) due to autoantibodies targeting desmosomal proteins.
Key Histological Features
- Suprabasal Acantholysis: Cleavage occurs immediately above the basal layer.
- “Row of Tombstones”: Basal keratinocytes remain attached to the basement membrane, resembling tombstones because their intercellular attachments are lost.
- Tzanck Cells: Rounded, detached acantholytic keratinocytes found within the blister cavity.
- Direct Immunofluorescence (DIF): Shows a characteristic “fishnet” or “chicken-wire” pattern of IgG and C3 deposition throughout the epidermis.
Pathophysiology Spotlight
| Target Antigen | Protein Type |
|---|---|
| Desmoglein 3 | Cadherin-type adhesion protein (found in desmosomes). |
| Desmoglein 1 | Often co-targeted; leads to more extensive cutaneous involvement. |
High-Yield Exam Pearl:
- Clinical Sign: A positive Nikolsky sign—blistering or sloughing of the skin when lateral pressure is applied to non-lesional skin—is classic for PV.
- PV vs. Bullous Pemphigoid (BP): PV causes intraepidermal splitting (flaccid bullae, mouth involvement common), whereas BP causes subepidermal splitting (tense bullae, mouth involvement rare).