Plasma Cell Gingivitis: A Clinicopathological Case Report Highlighting a Systematic Diagnostic Approach and Step-by-Step Surgical Management.

Plasma cell gingivitis (PCG) is a rare benign inflammatory condition characterized by diffuse erythematous gingival enlargement with dense plasma cell infiltration. Its clinical presentation overlaps with inflammatory, autoimmune, hematological, and plasma cell proliferative disorders, making accurate diagnosis challenging and necessitating a systematic clinicopathological evaluation. This report describes a 23-year-old male who presented with persistent gingival enlargement and bleeding involving the maxillary and mandibular anterior regions for two years despite repeated nonsurgical periodontal therapy and withdrawal of a suspected allergen. Clinical examination, hematological investigations, histopathological analysis, and immunohistochemical evaluation were performed to establish the diagnosis while excluding other plasma cell-rich lesions. Histopathological examination demonstrated a dense plasma cell-rich infiltrate, while immunohistochemical evaluation using CD19 supported a reactive plasma cell-rich lesion in correlation with the clinicopathological findings. Owing to the persistence of the lesion, external bevel gingivectomy was performed, followed by diode laser-assisted recontouring and placement of a periodontal dressing. The report provides step-by-step photographic documentation of the surgical procedure. Healing was uneventful, with restoration of physiologic gingival architecture and no recurrence during one year of follow-up. This case highlights the importance of a systematic diagnostic approach integrating clinical, hematological, histopathological, and immunohistochemical findings for the accurate diagnosis of PCG. It also demonstrates the step-by-step surgical management of persistent PCG and may serve as a practical guide for clinicians managing lesions refractory to conservative therapy.