Published: Jan 21, 2026
Key Information
Source
Year
2026
summary/abstract
Abstract
Background
Grade 2 or 3 uptake on 99mTc-pyrophosphate scintigraphy is a cornerstone for diagnosing transthyretin amyloidosis. However, light-chain amyloidosis can infrequently mimic this pattern, causing diagnostic error.
Case Summary
A 53-year-old man with heart failure presented with left ventricular hypertrophy and elevated biomarkers. Cardiac magnetic resonance suggested infiltration. 99mTc-pyrophosphate scintigraphy showed intense grade 3 (Perugini) uptake. However, immunofixation revealed an immunoglobulin G lambda clone. Fat and duodenal biopsies confirmed systemic light-chain amyloidosis (AL).
Discussion
Grade 3 uptake in AL is a rare diagnostic "false flag" signifying heavy infiltration. Hematologic evaluation is mandatory in patients with positive uptake to avoid misclassification.
Take-Home Messages
Grade 3 uptake in AL is an infrequent finding indicating advanced myocardial infiltration and poor prognosis. Hematologic screening is mandatory before interpreting scintigraphy to prevent misclassifying severe AL as transthyretin amyloidosis.
Visual Summary
Authors
Kevin Zambrano Zambrano MD a, Julio Martínez Salazar MD a, Jason Cedric Velarde Michaud MD a, Brian de Jesús Bernal Alferes MD a, Emmanuel Ortega Martínez MD a, Carlos Emiliano Fernández Sánchez MD a, Luis Montiel López MD a, Alexis Zambrano Zambrano MD b