Hidden Figures: Occult Intra-Cardiac Metastases in Asymptomatic Neuroendocrine Tumor Patients

Abstract

Carcinoid heart disease is a devastating paraneoplastic consequence of unchecked hormone production from neuroendocrine tumors (NET) and often results in right-sided heart failure. While it occurs frequently in NET patients with carcinoid syndrome, cardiac metastases occur much less often and are usually only incidentally found. Gallium-68 dotatate (ga-68) is an imaging tracer which binds to somatostatin receptor 2 with greater avidity than Indium-111, the tracer used commonly in octreotide scans. Ga-68 PET/CT is the most sensitive study for detecting occult NET metastases and has emerged as the current imaging gold standard. We describe two cases from Vanderbilt University Medical Center and Stanford University Medical Center where asymptomatic patients with well-differentiated midgut NET were diagnosed with intra-cardiac metastases using ga-68 PET/CT. Management of these patients was altered based on the findings as they underwent extensive cardiac evaluation and initiation of therapy with octreotide. Fortunately, they have not suffered life-threatening cardiac complications seen in some NET patients, from other published series, such as bradycardia, heart block, syncope and arrhythmias. These possibilities suggest early cardiology evaluation and consideration of other therapies beyond octreotide, such as surgery or PRRT, may be essential for all NET patients found to have intra-cardiac metastases.

Added-value of molecular imaging in myocardial metastasis of an ileal neuroendocrine tumour treated with peptide receptor radionuclide therapy: a case report

“… 1 While CV develops in 50% of the patients with NET with carcinoid syndrome, cardiac metastases are much rarer and have been recorded in less than 5% of the population. 3 Calissendorff et al reported four patients with ileal NET and cardiac metastases detected by 68 Ga-Dotatoc PET/CT in a study whose incidence of cardiac metastases was 4.3%. 2…”

“…Therefore, 68 Ga-Dotatoc PET/CT had been accepted as the current gold standard for initial diagnosis and follow-up of patients with well-differentiated NET. 3 It has been established that this type of test makes it easier to carry out a definitive diagnosis and staging of NET in a non-invasive way. 4 …”

“…The myocardium is a rare location for carcinoid metastasis. Carcinoid heart disease is usually asymptomatic and can affect any of the cardiac chambers, the interventricular septum, or the pericardium, 3 and can go unnoticed in a significant percentage of cases.…”

“…On the other hand, carcinoid valvulopathy (CV) is a significant cause of morbidity and mortality in patients with metastatic NET. 3 Contrary to what happens with cardiac metastases (CM), functional imaging is not essential in the diagnosis of CV for it is not based on the expression of SSTR, but on the release of vasoactive substances by the tumour as a result of chronic exposure to excessive levels of circulating serotonin, which generate fibrous plaques that are deposited on the heart valves. 1 , 3 These types of lesions frequently appear in small intestine NET cases, mainly affecting the right-sided chambers, which can be assessed in an echocardiogram, revealing possible progressive valvular dysfunction.…”

Hybrid imaging of neuroendocrine tumors in the heart: Union is strength

“…In general, however, the cardiac localization of NETs is very difficult to depict by conventional radiological techniques. Functional PET Precursor of all endogenous catecholamines, is taken up through L-type amino acid transporters 68 Ga-DOTA-Phe 1 -Tyr 3octreotide (DOTATOC), ,…”