Plasma Cell precursor and Other Disorders

Category: Plasma Cell precursor and Other Disorders

Diagnostic patterns and outcomes of amyloidosis screening in a monoclonal gammopathy clinic: a single center study

(PA-348) Diagnostic Patterns and Outcomes of Amyloidosis Screening in a Monoclonal Gammopathy Clinic: A Single Center Study

Wednesday, September 17, 2025

swarup Kumar, MD

MD
UCONN HEALTH

Introduction: Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) are precursor plasma cell disorders with potential to progress to symptomatic disease, including light chain amyloidosis (AL). Early identification of patients at risk is critical; delayed diagnosis of AL is associated with poor outcomes. Dedicated MGUS clinics at academic medical centers provide a structured approach for monitoring, enabling timely detection of progression. Incorporating screening tools such as abdominal fat pad aspiration (FPA) enhances early diagnosis of subclinical AL. Understanding transformation risk—estimated at ~1% per year for MGUS and higher for SMM—further supports the utility of such clinics in guiding surveillance and management strategies.

Methods:   The patient cohort included in this study spans January 2022 through May 2025 at a single center academic institution MGUS clinic. The cohort includes those who underwent both bone marrow biopsy (BMB) and FPA for amyloidosis screening. Reported indications for performing screening FPA were diagnosis of cardiomyopathy, biopsy proven localized amyloidosis, nephrotic range proteinuria and smoldering myeloma.

Results:   Between 2022 and 2025, a total of 417 patients were evaluated in the MGUS clinic. Amongst the MGUS patients, 74 underwent BMB, and 40 bedside abdominal FPA based on clinical indications that included biopsy proven localized amyloidosis (n=6), nephrotic range proteinuria (n=8), cardiomyopathy (n=12), SMM (n=9) and peripheral neuropathy (n=5). Imaging studies included 49 PET/CT scans and 54 skeletal surveys to evaluate for multiple myeloma (MM). Systemic AL amyloid was diagnosed in 4 patients by screening FPA (3) and BMB (4). Biopsy-proven localized amyloid cases included 5 pulmonary and 1 laryngeal site. An additional 3 patients who were diagnosed with localized amyloidosis (2 laryngeal, 1 pulmonary) and referred to the MGUS clinic did not have evidence of MGUS. Overall, in the MGUS clinic, 9.5% of patients were screened for AL with FPA. Of all patients seen, 3.1% were found to have AL amyloid.

Conclusions:   While association with progression from MGUS and SMM to MM are well known and frequently monitored in many outpatient settings, monitoring for and diagnosing AL can be easily overlooked. Patients with MGUS and smoldering multiple myeloma benefit from dedicated clinics that employ protocol-driven screening for AL amyloidosis, enabling earlier detection and improved outcomes. For patients with immunoglobulin light chain (LC) abnormalities, FPA and BMB will demonstrate AL in over 85% of patients. Further, reports from Mayo Clinic demonstrate that 9% of all MGUS patients seen are subsequently found to have AL, higher than rates seen at our center, highlighting the need for improved screening practices.