Factor X deficiency: an uncommon presentation of AL amyloidosis.

Factor X deficiency is the most common coagulation factor deficiency amongst patients with AL amyloidosis. It presumably occurs due to adsorption of factor X to amyloid fibrils. The deficiency of this factor, in conjunction with other hemostatic defects, can cause bleeding complications. A case of acquired factor X deficiency due to AL amyloidosis is reported, where abnormal coagulation parameters were the only presenting feature.