label: Primary Systemic Amyloidosis
label_lc: primary systemic amyloidosis
description: "A plasma cell neoplasm that secretes an abnormal immunoglobulin, which deposits in various tissues and forms a beta-pleated sheet structure that binds Congo red dye with characteristic birefringence.  The sites of involvement include heart, liver, kidney, gut, tongue, nerves, and bone. (WHO, 2001)"