Pemphigus Vulgaris Mimicking Behçet's Syndrome With Oral and Vulvar Ulcers: A Case Report.

Recurrent oral and genital ulceration commonly raises suspicion for Behçet's syndrome, but the oral-genital pattern is not specific and should prompt a structured differential diagnosis, particularly in mucosa-predominant presentations without systemic features. We report a 62-year-old woman referred for a four-month history of synchronous, painful oral and vulvar mucosal lesions associated with odynophagia/dysphagia and 9% unintentional weight loss. She had no ocular symptoms, no cutaneous lesions, and routine laboratory testing was globally unremarkable. Behçet's syndrome was initially considered, and empiric therapy with colchicine followed by systemic corticosteroids was instituted without clinical improvement. An oral mucosal biopsy was therefore performed, and histopathology with direct immunofluorescence established the diagnosis of pemphigus vulgaris. This case highlights pemphigus vulgaris as a clinically plausible Behçet mimic when oral and genital mucosal disease coexist, and underscores the value of timely biopsy with immunofluorescence in refractory oral-genital erosive disease.