Paraneoplastic pemphigus associated with small lymphocytic lymphoma: A case report.

INTRODUCTION Paraneoplastic pemphigus (PNP) is a life-threatening autoimmune blistering disease associated with underlying neoplasms. Currently, this disease is very difficult to treat. PATIENT CONCERNS We reported a rare case of paraneoplastic pemphigus associated with small lymphocytic lymphoma responsive to desmoglein 3 (Dsg3) and bullous pemphigoid (BP) antigen 180. DIAGNOSES The initial diagnosis was hypothesized to be Stevens-Johnson syndrome based on the severe mucosal erosion and polymorphous skin lesions. However, the histopathological examination of the skin biopsy and immunology revealed PNP. INTERVENTIONS Anti-tumor therapy, immunosuppression and anti-infective therapy were administered. OUTCOMES After a series of treatments, the skin lesions had been alleviated remarkably. Enzyme-linked immunoassays indices for Dsg3 and bullous pemphigoid antigen 180 decreased (Dsg3, 32; bullous pemphigoid antigen 180, 70.44). Unfortunately, 2 months later, the patient suffered respiratory failure due to the lung impairment of small lymphocytic lymphoma and infection. Eventually, the patient chose to be discharged from the hospital and lost the opportunity for follow-up treatment as he could not afford the expensive treatment costs. LESSONS It is highly susceptible to misdiagnosis due to polymorphous skin lesions. In this case, it was also initially misdiagnosed as Stevens-Johnson syndrome. Therefore, we should pay great attention to differential diagnosis. When refractory stomatitis and mucosal erosions occur, the possibility of PNP should be considered first. At the same time, pathology, immunology and other related tests as well as the examination of primary tumors should be carried out as soon as possible.