Paraneoplastic pemphigus associated with Castleman tumor: a commonly reported subtype of paraneoplastic pemphigus in China.

BACKGROUND Castleman tumor, a rare lymphoproliferative disorder, is one of the associated tumors in paraneoplastic pemphigus. We analyzed the characteristics of a group of patients with Castleman tumor to clearly understand and to improve the prognosis of the disease. OBSERVATIONS Ten cases of paraneoplastic pemphigus associated with Castleman tumor treated in the Department of Dermatology, Peking University First Hospital, Beijing, China, from May 1, 1999, to March 31, 2004, were analyzed for clinical aspects, characteristics and histologic features of the tumors, and computed tomographic findings. Literature was reviewed and data were compared with our cases. Castleman tumor was a frequently reported neoplasm in association with paraneoplastic pemphigus in China. The disease was found to be caused by an autoimmune reaction originating from the B lymphocytes in the Castleman tumor. CONCLUSIONS Castleman tumor in association with paraneoplastic pemphigus is a commonly reported subtype of paraneoplastic pemphigus in China. Early detection and removal of the Castleman tumor are crucial for the treatment of this tumor-associated autoimmune disease.