Pathology · single question
A patient is diagnosed with pemphigus vulgaris. Which test best confirms the diagnosis?
Show answer and explanation
Correct answer: C. Direct immunofluorescence
- A. Routine excisional/H&E biopsy shows suprabasilar acantholysis but is not the confirmatory test of choice.
- B. Exfoliative cytology may show Tzanck cells but is not confirmatory.
- C. Correct. DIF demonstrates intercellular IgG ('chicken-wire' / fishnet) deposits around keratinocytes — the diagnostic confirmation.
- D. Brush biopsy is a screening tool, not confirmatory for PV.