Pemphigus vulgaris macroscopically and cytologically resembling oral squamous cell carcinoma

We describe the clinical, macroscopic, cytological, histopathological, immunohistochemical, serodiagnostic and aspects of pemphigus vulgaris (PV) in the oral gingiva that clinically mimicked oral squamous cell carcinoma (OSCC) in a 57-year-old Japanese man. He developed slight haphalgesia of the buccal gingiva around teeth numbers 18 and 19 2 years ago. A dentist diagnosed intractable ulcer, but the patient ignored the condition for about 2 years until a sharp pain in the gingiva worsened. He consulted an otolaryngologist, who referred the patient to our hospital under a cytological diagnosis of OSCC. An oral examination revealed several extensive painful erosions/ ulcers from the buccal and lingual gingiva around teeth numbers 18 to 21 to the distal alveolar mucosa of no. 18 and the buccal and lingual gingiva around tooth number 31. A presumptive diagnosis of PV with dysplastic changes was determined from cytological smears. The cytological Nikolsky test was positive. The diagnosis of PV was confirmed from clinical and histopathological findings of a biopsy specimen obtained from the perilesional site. Although the definitive diagnosis of PV required only 2 weeks after this patient presented at our hospital, 2 years had elapsed since the onset of oral lesions.