Acquired von Willebrand's disease in association with Wilm's tumor: regression following treatment.

A 9-yr-old female presented with a Wilm's tumor and a coagulopathy consistent with von Willebrand's disease. Factor VIII procoagulant activity (VIII C), factor VIII related antigen (VIIIR:Ag), and von Willebrand factor activity (VIII:vWf) were decreased. There was no evidence for a circulating inhibitor of the factor VIII molecular complex. von Willebrand's antigen II (vW AgII), which is deficient in hereditary von Willebrand's disease, was decreased below detectable levels in this patient. The coagulation studies, VIIIR:Ag, and vW AgII levels returned to normal following therapy of the Wilm's tumor. Wilm's tumor must be included as one of the malignancies associated with acquired von Willebrand's disease. Immunofluorescent studies of the tumor specimen showed normal endothelial staining of VIIIR:Ag by semiquantitative techniques and a lack of specific tumor adsorption of VIIIR:Ag The presence of normal amounts of tissue VIIIR:Ag has not previously been demonstrated in acquired von Willebrand's disease. Since we failed to demonstrate an inhibitor in the plasma in this patient, the etiology of the acquired von Willebrand's disease in this patient appears to differ from other cases of acquired von Willebrand's disease. The finding that vW AgII is decreased in this patient, similar to that reported in hereditary von Willebrand's disease, supports the close association of vW AgII to VIIIR:Ag, even though they are immunologically and biochemically distinct.