{Reference Type}: Case Reports {Title}: A Complex Case of Extensive Systemic Amyloidosis With Underlying Monoclonal Gammopathy. {Author}: Syed F;Hassan MA;Joy J;Awolumate OJ;Nwaogwugw U; {Journal}: Cureus {Volume}: 15 {Issue}: 8 {Year}: 2023 Aug 暂无{DOI}: 10.7759/cureus.43753 {Abstract}: Systemic amyloid light chain, or primary amyloidosis (AL amyloidosis), is a serious medical condition that leads to the deposition of abnormal proteins called amyloid fibrils in various organs of the body. AL amyloidosis can present with different symptoms, which can make diagnosis challenging. This case report presents a clinical scenario of a 53-year-old female patient who had come in for shortness of breath and lower extremity swelling and was found to have acute on chronic pulmonary embolism. The patient had a history of systemic amyloidosis diagnosed with a kidney and duodenal biopsy. She also had a bone marrow biopsy done and was found to have IgG monoclonal gammopathy. Throughout the hospital course, patients required cautious diuretic use given the worsening kidney function. She was given intravenous anticoagulation initially and later switched to oral medication on discharge. Due to the aggressive nature of amyloidosis, a decision was made to start the patient on chemotherapy in an outpatient setting. This case presents an interesting scenario of systemic amyloidosis with concomitant monoclonal gammopathy that was complicated by acute pulmonary embolism. The case is important as it shows the different levels of amyloidosis and teaches us the benefit of taking a multidisciplinary approach to making a concrete plan for patients with advanced amyloidosis disease.