Immunoglobulin Light Chain Amyloidosis Presenting as Inferior Vena Cava Thrombosis

Immunoglobulin light chain (AL) amyloidosis is a rare disease characterized by the deposition of misfolded extracellular proteins within various body tissues resulting in dysfunction of the cardiac, renal, gastrointestinal, hematologic, and nervous systems, among others. Systemic AL amyloidosis often presents with a constellation of vague symptoms such as fatigue, dyspnea, and abdominal pain. Untreated AL amyloidosis with cardiac involvement is rapidly fatal with a median survival of 6 months. In this report, we will highlight the case of a 43-year-old female who presented with generalized abdominal symptoms and fatigue. She was found to have extensive inferior vena cava (IVC) thrombosis extending into the renal veins bilaterally in the setting of nephrotic range proteinuria, new onset arrhythmia, diastolic heart failure, gastrointestinal, and autonomic dysfunction. She received systemic thrombolytic therapy for the IVC and renal vein thrombosis. The multiorgan involvement led us to consider the possibility of amyloidosis. Abdominal fat pad biopsy was performed as part of the diagnostic effort. The abdominal fat pad biopsy did not reveal AL amyloidosis. Ultimately, the diagnosis of systemic AL amyloidosis was made on the basis of pathology from luminal biopsies obtained during outpatient esophagogastroduodenoscopy that was performed days prior to her admission. Unique to our case is the patient presentation with extensive thrombotic disease of the IVC and renal veins. It is important to understand the disease process, presenting signs and symptoms as well as diagnostic essentials based on current literature in order to minimize the morbidity and mortality of this rare disease.