Pemphigus vulgaris (PV) is a chronic autoimmune blistering disorder primarily affecting the oral mucosa. Approximately 70% of patients initially present with oral ulcers, and in 50% of these cases, the lesions remain confined to the oral cavity in early disease stages (Amagai, 2006). Due to overlapping clinical features, PV is frequently misdiagnosed as oral squamous cell carcinoma (OSCC),with reported misdiagnosis rates ranging from 30% to 50%?(Kasperkiewicz et al., 2017). Such diagnostic delays—typically 6 to 10 months—often result in unnecessary surgical interventions.We present a case of PV initially misdiagnosed as buccal carcinoma, leading to radical resection. This case highlights two key insights:A novel standardized diagnostic algorithm integrating clinical presentation, histopathology, and serological testing?for improved differentiation.The critical role of multidisciplinary collaboration?in reducing diagnostic delay (definitive diagnosis was achieved within 5 days post-surgery.