Paraneoplastic Pemphigus Associated With Renal Cell Carcinoma. Rare Case Report and Literature Review.

INTRODUCTION: Paraneoplastic pemphigus (PNP) is an uncommon autoimmune blistering disorder frequently associated with underlying malignancies. Renal cell carcinoma (RCC) is the most common primary renal cancer. It is associated with a wide range of paraneoplastic syndromes, but occasionally presents as a dermatological finding. CASE PRESENTATION: A 56-year-old woman with severe oral and cutaneous lesions was diagnosed with PNP associated with renal cell carcinoma (RCC). The patient was treated with 1 g of rituximab as an infusion, and after two weeks, another dose of 1 g of rituximab was administered in combination with steroids (prednisolone 0.5 mg/kg) until control, then gradually decreasing by 25% each month, until we reached 5 mg/day. The patient achieved complete clinical remission at 6 months; however, long-term outcomes remain unknown because she was subsequently lost to follow-up. CONCLUSION: A comprehensive workup is crucial for diagnosing the underlying tumor associated with this phenomenon. Rituximab- and steroid-based therapies may be effective in controlling PNP symptoms.