OBJECTIVEPlasma 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 DESIGNTwo 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.RESULTSCases 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.CONCLUSIONSDiagnosing 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.