Fatal paraneoplastic pemphigus associated with a mediastinal tumor

Paraneoplastic pemphigus (PNP) is a rare life‐threatening autoimmune bullous skin disease which is an obligate paraneoplasma. A 34‐year‐old woman presented with recalcitrant stomatitis and a generalized lichenoid rash. A diagnosis of PNP was established based on clinical findings, immunofluorescence, histopathology and biochemistry. A localized mediastinal mass was found with CT imaging and excised. The histologic diagnosis was dendritic cell sarcoma. Despite removal of tumor and immunosuppressive therapy, the PNP progressed rapidly and the patient died of septic multiorgan failure.