Amyloidosis: current approaches for diagnosis and treatment

Amyloidosis is a complex disease resulting from the extracellular deposition of fibrous degradation proteins in body tissues. The type of protein deposited determines the class of amyloidosis present. Morphological, cytochemical, and immunohistochemical studies allow one to precisely identify the class of amyloid present and, therefore, more appropriately select a therapy. Rectal biopsy is the preferred initial procedure for obtaining tissue for study; however, subcutaneous fat pad, gingival, skin, and bone marrow biopsies are alternative noninvasive biopsy sites. We have presented two patients with multiple myeloma and amyloidosis of the AL type. One patient presented with multi-organ failure of undetermined etiology and the other with asymptomatic hepatosplenomegaly. The diagnosis of amyloidosis was made by bone marrow biopsy in the first patient and rectal biopsy in the second patient using morphological studies and confirmed cytochemically with the congo red stain. The type of amyloidosis was determined with immunohistochemical studies. Their clinical course and response to therapy will be assessed by repeated immunoglobulin studies, liver and spleen size, and studies for organ dysfunction such as 2-D echo and level of proteinuria.