Castleman's tumor and erosive lichen planus: Coincidence or association?

The rare association of severe erosive lichen planus and Castleman's tumor is presented. Castleman's tumor, or giant lymph node hyperplasia, is a benign neoplasm resembling thymic tumors and is associated with several immunologic abnormalities. Lichen planus also is associated with immunologic defects. One hypothesis linking these two diseases is that lymphocytes may become sensitized to tumor antigens on the Castleman's tumor and attack cross-reacting structures in the skin and other stratified squamous mucosae to produce the clinical picture of lichen planus.