A80-3-41 The Nodule That Got to the Heart of the Matter: An Atypical Presentation of Cardiac Amyloidosis as a Pulmonary Nodule

Abstract Introduction Cardiac amyloidosis is a condition characterized by extracellular deposition of insoluble protein within the cardiac tissue. Transthyretin (ATTR) cardiac amyloidosis is an increasingly recognized but underdiagnosed cause of restrictive cardiomyopathy in older adults. Affected patients typically present with symptoms of heart failure or arrhythmias that are usually identified through cardiac imaging findings and cardiac biopsy. Atypical presentations of cardiac amyloidosis can delay diagnosis and treatment. This is a case of wild-type ATTR amyloidosis that initially presented mimicking a pulmonary malignancy in an elderly male. Case Presentation A 79-year-old male with a past medical history of coronary artery disease (status post 5-vessel bypass surgery and previous infarction), hypertension, hyperlipidemia, type 2 diabetes, and a prior smoking history who presented with a 6-month history of a nonproductive cough and dyspnea on exertion. His initial workup included an echocardiogram that showed an ejection fraction of 45%. CT imaging showed a 1.5 cm peripheral nodule that was non-FDG avid on PET/CT. He made clinical progress with management of his heart failure, and serial follow-up imaging showed stability of the nodule. However, two years from the initial evaluation, the nodule unexpectedly enlarged to 1.9 cm (Figure 1) with new FDG avidity on repeat PET/CT, raising concern for malignancy. The suspicious nodule was resected, with histopathology revealing necrotizing granulomatous inflammation with amyloid deposition confirmed by Congo red staining. Mass spectroscopy identified wild-type ATTR amyloidosis. Cardiac MRI demonstrated a non-ischemic cardiomyopathy with diffuse delayed enhancement and biventricular involvement. A technetium-99m pyrophosphate scan showed grade 3 myocardial uptake, confirming ATTR cardiac amyloidosis. He was started on Tafamidis and now, two years later, his heart failure has come under much better control. Discussion This case presents a rare instance in which a pulmonary nodule served as the initial manifestation of cardiac amyloidosis. It highlights that even nodules appearing suspicious for malignancy on PET imaging could, in fact, be due to amyloidosis. Despite the presence of cardiac symptoms at presentation, this case was unique in that the clinical features were not consistent with the typical manifestations of cardiac amyloidosis. Heart failure with preserved ejection fraction is the usual presentation of cardiac amyloidosis; this patient instead had heart failure with a reduced ejection fraction. His prior MI and CAD are potential contributors to this atypical picture. In summary, keeping a broad differential in mind is important, especially in elderly patients who present with suspicious lung nodules. This abstract is funded by: None