Unusual clinical presentations of plasma cell mucositis involving oral mucosa: Presentation of 2 cases and review of the literature.

OBJECTIVE: Plasma cell mucositis (PCM) is a non-neoplastic plasma cell disorder of the upper aerodigestive tract with a high impact on life quality. Less than 70 cases were reported in the literature. The objective of this study was to report 2 cases of PCM. A concise review of the literature is also presented. STUDY DESIGN: Two cases of PCM that presented during the COVID-19 quarantine are reported. The inclusion criteria for the literature review were English-indexed case reports of the last 20 years. RESULTS: Cases were treated with meprednisone. As mechanical trauma was proposed as a triggering factor, its control was also considered. Patients were followed with no relapses. There were 29 studies included. The mean age was 57 years, with a male predominance, different clinical phenotypes, and intensely erythematous mucosa as a classical finding. The most frequent site was the lip, followed by the buccal mucosa. The final diagnosis is clinicopathologic. CD138 expression is a hallmark of plasma cells, frequently aiding PCM diagnosis. Plasma cell mucositis treatment is mostly symptomatic, and several therapeutic modalities have been mostly unsuccessful. CONCLUSIONS: Diagnosing plasma cell mucositis becomes challenging as many lesions may mimic other conditions. Consequently, in these cases, the diagnostic process should gather clinical, histopathologic, and immunohistochemical data.