Gastroenteropancreatic Neuroendocrine Tumor Metastasis to the Heart: Evaluation of Imaging Manifestations.

Neuroendocrine tumors (NET) may affect the heart by cardiac metastasis or carcinoid heart disease. NET metastasis to the heart is rare, with limited data characterizing it. We sought to evaluate Ga-DOTATATE PET scan imaging features and associated cardiac imaging characteristics where available in those with NET cardiac metastases. Ga-DOTATATE positron emission tomography (PET)/CT scans performed on patients with gastroenteropancreatic (GEP) NET at our institution were reviewed for cardiac involvement. Those identified with cardiac metastases had their electronic medical record, transthoracic echocardiogram (TTE) and cardiac magnetic resonance imaging (MRI) reviewed for characterization. From a total of 1426 Ga-DOTATATE PET/CT scans performed on patients with GEP-NET, 25 (1.75%) had cardiac uptake consistent with metastasis. Of these, 22 had myocardial metastases (29 distinct myocardial lesions: left ventricle - 16, right ventricle - 6, and ventricular septum -7) and 3 had periradial lymph node involvement only. NET patients with cardiac metastases as identified by DOTATATE scan did not appear to have any hemodynamically significant TTE features, aside from those (2/25) who had concomitant carcinoid heart disease. Of the 14 patients who had available TTE for review, only one with high metastatic cardiac tumor burden had detectable cardiac mass. Of the 6 cases who had available MRI, all had metastatic cardiac lesions seen with excellent correlation with tumor localization on Ga-DOTATATE PET scan. Ga-DOTATATE PET has excellent capability for the diagnosis of cardiac NET metastasis. Cardiac MRI may provide further anatomic and tissue characterization evaluation. Those with myocardial NET metastases without carcinoid heart disease did not have significant hemodynamic effect based on echocardiographic criteria.