# Incidental Cardiac Uptake on 99mTc-HMDP Bone Scintigraphy in Oncology Patients: Two Cases of Transthyretin Amyloid Cardiomyopathy with Literature Review

## TL;DR

This paper reports two cases where bone scans in cancer patients revealed heart issues linked to a rare heart disease, highlighting the importance of this incidental finding for early diagnosis.

## Contribution

The novelty lies in demonstrating how bone scintigraphy can incidentally detect transthyretin amyloid cardiomyopathy in oncology patients.

## Key findings

- Two elderly breast cancer patients showed myocardial uptake on 99mTc-HMDP scans, leading to diagnosis of ATTRwt-CM.
- Literature review summarizes cardiac uptake frequency and clinical relevance in cancer patients.
- Early detection via bone scintigraphy may improve outcomes for ATTRwt-CM.

## Abstract

Background: Bone scintigraphy using technetium-99m hydroxymethylene diphosphonate (99mTc-HMDP) is extensively employed to detect bone metastases. However, incidental myocardial uptake may indicate wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM), a frequently overlooked diagnosis with important clinical implications. Case Presentation: Two elderly female patients with a history of breast cancer were subjected to 99mTc-HMDP bone scintigraphy as part of a routine evaluation for possible bone metastases. Both cases demonstrated incidental myocardial uptake (Perugini Grade 2 and Grade 3, respectively), raising suspicion for ATTRwt-CM, which was subsequently confirmed by endomyocardial biopsy. Review of the Literature: We reviewed published studies reporting cardiac uptake on bone scintigraphy, summarizing the frequency, patient demographics, and tracer types, and emphasizing the clinical relevance of this finding in cancer patients. Conclusions: In oncology patients, bone scintigraphy performed during routine metastatic screening may facilitate early detection of ATTRwt-CM, enabling timely diagnosis and treatment initiation, potentially improving clinical outcomes.