[Clinical analysis of 9 cases of paraneoplastic pemphigus with oral damage].

<b>Objective:</b> Summarize the clinical characteristics, treatment methods, and prognosis of paraneoplastic pemphigus with oral lesions, and identify commonalities and features to provide better references for the clinical diagnosis and treatment of this disease. <b>Methods:</b> A retrospective analysis was conducted on the case data and clinical photos of 9 patients with paraneoplastic pemphigus accompanied by oral lesions treated in the Internal Medicine Ward and Department of Stomatology of Beijing Hospital from September 2017 to December 2023, and the clinical characteristics were summarized and analyzed. <b>Results:</b> All 9 patients had oral mucosal and skin lesions simultaneously, in whom visceral tumors were found upon systemic examinations, including 4 cases of Castleman's disease, 4 cases of thymoma, and 1 case of lung cancer. All patients had received glucocorticoid therapy before a clear diagnosis, but the effect was not significant. After removing the primary tumor, corticosteroid intravenous or oral therapies were usually continued, supplemented with immunoglobulin and immunosuppressants for treatment, which could achieve significant therapeutic effects. With primary tumor resection, 6 patients continued to receive corticosteroid intravenous or oral treatment for 6 to 12 months, supplemented with immunoglobulin and immunosuppressants. Oral mucosal erosion improved significantly and skin lesions were relieved. Three patients who were unable to remove their primary tumor continued with the previous glucocorticoid treatment regimen and died within one year. However, local treatment of their oral cavity during the treatment process still helped alleviate oral mucosal pain, promote erosion healing, and improve nutritional status. <b>Conclusions:</b> Multiple erosions of the oral mucosa and polymorphic skin damages are common clinical manifestations of paraneoplastic pemphigus. Castleman's disease and thymoma are common coexisting tumors. Early diagnosis and timely surgical resection of tumors are crucial for treatment and prognosis. The application of glucocorticoids and local oral treatment after resection is effective.