Plasma Cell Mucositis: A 20‐Year Retrospective Review at a Tertiary Center

ABSTRACT Background Plasma cell mucositis (PCM) is a rare, chronic inflammatory condition of mucosal surfaces that is likely underdiagnosed and underreported, with limited data on its clinical characteristics, extracavitary involvement, and treatment outcomes. Objectives To characterize the clinical presentation, comorbidities, and treatment patterns of PCM in a cohort of patients from a tertiary care center. Methods We conducted a retrospective cohort study of histopathologically confirmed PCM cases diagnosed at a tertiary care center between 2004 and 2024. Cases were identified based on clinicopathologic correlation demonstrating a polyclonal plasma cell–rich infiltrate. Demographic data, clinical features, comorbidities, laboratory findings, and treatment outcomes were collected and analyzed descriptively. Results Ten patients were included, of whom 7 (70%) were aged ≥ 50 years and 6 (60%) were male. Genital involvement was observed in 6 patients (60%), whereas oral involvement occurred in 4 (40%). Symptom duration exceeded 2 years in 6 patients (60%). Concurrent malignancies were identified in 4 patients (40%), and autoimmune conditions in 2 (20%). Treatment responses were heterogeneous; topical corticosteroids were the most consistently effective therapy, while systemic immunosuppressive agents were required in 3 patients (30%) with variable outcomes. Patch testing identified contact allergens in 2 patients, with improvement following allergen avoidance. Conclusions PCM is a rare and often chronic condition with heterogeneous clinical manifestations and variable therapeutic responses. Genital involvement may be more common than previously recognized. Management remains challenging, highlighting the need for improved understanding of disease pathogenesis and development of more effective treatment strategies.