Oral-limited pemphigus vegetans with anti-desmoglein 1 antibody positivity in an elderly woman: a case report and literature review

Background Pemphigus vegetans (PVg) is a rare variant of pemphigus vulgaris. Oral-limited disease is uncommon, and atypical serology may complicate diagnosis. Case presentation A 66-year-old woman presented with recurrent painful oral erosions of more than 3 months’ duration. Examination showed vegetative and pustular lesions of the bilateral buccal mucosa, dorsal tongue, palate, floor of the mouth, and gingiva, with a cerebriform tongue and positive Nikolsky sign. No cutaneous, genital, or nail involvement was identified. Histopathology showed papillomatous epithelial hyperplasia, suprabasal clefting and acantholysis, with eosinophil- and neutrophil-rich intraepithelial microabscesses. Direct immunofluorescence demonstrated intercellular IgG and C3 deposition in a reticular pattern, with negative IgA and IgM staining. Serum anti-Dsg1 was positive at 24.60 U/mL, whereas anti-Dsg3 was negative (< 5.00 U/mL); anti-BP180 and anti-BP230 antibodies were also negative. The clinical presentation was considered most consistent with Hallopeau-type pemphigus vegetans. Prednisone was initiated at 40 mg/day on October 28, 2024, and gradually tapered to 10 mg/day. Initial clinical improvement was documented, and the oral mucosa remained clinically stable at the last follow-up on April 1, 2026, approximately 17 months after treatment initiation. Conclusion This case illustrates that oral-limited pemphigus vegetans may occur with an atypical anti-Dsg1-positive/anti-Dsg3-negative profile. Diagnosis should integrate clinical morphology, histopathology, and direct immunofluorescence rather than rely on serology alone.