BackgroundPemphigus vulgaris (PV) is a kind of rare and severe autoimmune bullous disease. In this case, the specificity of oral PV lies in the clinical manifestations of a single palatal ulcer, and no blisters were found in the oral mucosa. This case provides a powerful reference for dentists diagnosing and treating oral PV with atypical clinical presentations.Case presentationA 54 years old female patient presented with a non-healing palatal gingival ulcer for over three months. By histopathological H&E staining and the direct immunofluorescence (DIF) test, the final diagnosis was oral PV. After topical glucocorticoid therapy, the affected area was cured.ConclusionsIn patients with prolonged erosion of the skin or oral mucosa, even if complete blisters are not visible, the physician should consider autoimmune bullous diseases and pay attention to avoid diagnostic defects.