Increased frequency of oral plasma cell mucositis/plasma cell gingivitis after the COVID-19 pandemic: a 23-year retrospective analysis and review of diagnostic challenges relating to this condition.

OBJECTIVE: Oral plasma cell mucositis (PCM) or localized plasma cell gingivitis (PCG) is an idiopathic inflammatory condition often associated with hypersensitivity reactions. This study aimed to evaluate the frequency and features of PCM/PCG in a large biopsy service over a time period of more than 20 years. STUDY DESIGN: The biopsy archives at University of Florida College of Dentistry were searched from 2000 through the first quarter of 2023 for cases of oral PCM or PCG. Case data were aggregated and analyzed. RESULTS: A total of 107 cases were included. Between 2000 and 2019, PCM/PCG was diagnosed in 0.03% of all biopsy cases. Starting in 2020 through 2023, the percentage of biopsies diagnosed as PCM/PCG increased threefold to 0.10% of all biopsy cases, and the mean patient age increased by 3 years. There were no statistically significant differences between cases diagnosed from 2000 to 2019 and those from 2020 to 2023 regarding age, sex, location, or histology. CONCLUSIONS: A significant increase in PCM/PCG was identified in this study at one institution coinciding with the start of the COVID-19 pandemic. Further investigation is recommended to determine if this is a widespread phenomenon and identify possible etiologic mechanisms.