A rare presentation of plasma cell cheilitis: case report and review of management strategies.

Introduction and importance: Plasma cell cheilitis is a rare, benign, and idiopathic inflammatory disorder that affects the lips. This report presents an uncommon case involving the lower lip, successfully treated by surgical excision. Additionally, a concise review of the literature on its management is provided. Presentation of the case: A 63-year-old female patient presented with a nonhealing lesion on the left side of her lower lip, persisting for 1 year. Clinical evaluation identified a nontender, firm, crusted lesion with distinct margins, measuring approximately 2 cm × 1 cm. The lesion was excised, involving the underlying connective tissue. Biopsy confirmed that the surface was lined by keratinized stratified squamous epithelium, with dense inflammatory infiltrates in the dermis, predominantly consisting of mature plasma cells. Immunohistochemistry analysis demonstrated polyclonal plasma cell positivity for both kappa and lambda light chain markers and significant expression of CD138. Additionally, minor populations of lymphoid cells were identified using CD5, while CD45 positivity indicated lymphoplasmacytic infiltration. The postoperative period was uncomplicated, with no adverse events reported during the 2-year follow-up. Clinical discussion: Some lesions have shown resistance or recurrence following medical therapy, and malignant transformation has been reported in a few long-standing cases. Therefore, surgical excision may serve as the primary treatment modality for plasma cell cheilitis. Conclusion: Plasma cell cheilitis should be included in the differential diagnosis of persistent lesions of the lower lip. Accurate diagnosis necessitates comprehensive histopathological and immunohistochemical evaluation. Further research with a higher level of evidence is recommended to validate these findings.