Paraneoplastic pemphigus (PNP) most characteristically shows which unique DIF pattern that distinguishes it from other pemphigus variants?
- A Intercellular IgG only
- B Intercellular IgG + linear C3 at BMZ ✓
- C Linear IgG at BMZ only
- D Granular IgA in dermal papillae
Correct answer: B. Intercellular IgG + linear C3 at BMZ
Explanation
PNP shows a combined DIF pattern: intercellular IgG (due to anti-desmoglein antibodies) and linear/granular complement at the BMZ (due to anti-envoplakin, anti-periplakin, anti-desmoplakin antibodies). This combined pattern in the context of an underlying neoplasm (most commonly non-Hodgkin lymphoma or CLL) is characteristic. The target antigens are plakins (envoplakin, periplakin, desmoplakin) and BP230.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.