Paraneoplastic pemphigus associated with follicular dendritic cell sarcoma arising from Castleman's tumor.

Paraneoplastic pemphigus (PNP) is associated with various forms of underlying neoplasia. We report a patient with PNP associated with an intraabdominal follicular dendritic cell sarcoma that developed from a Castleman's tumor that had preexisted for 40 years.