Malignant papillary cystadenoma lymphomatosum.

Histogenesis and histology of papillary cystadenoma lymphomatosum (PCL) is summarized. A case is described in detail in which PCL recurred after surgical removal and the epithelial elements of the PCL underwent malignant transformation. The literature of similar cases is reviewed and the alternatives for the histogenesis of malignant PCL is briefly discussed.