Imaging of Myocardial Carcinoid Metastasis

Neuroendocrine tumors (NETs) are indolent neoplasms that may metastasize to the heart, though myocardial involvement is under-recognized and often asymptomatic. We present a case series of 2 patients with metastatic NETs and isolated cardiac metastases without valvular involvement, highlighting the role of multimodality imaging. In both cases, cardiac metastases were initially identified on Gallium-68 DOTATATE positron emission tomography/computed tomography and further characterized by cardiac magnetic resonance (CMR), while transthoracic echocardiography had limited ability to identify myocardial metastases. One patient developed progressive ventricular outflow tract obstruction requiring surgical resection, whereas the other demonstrated stable disease with subsequent development of nonischemic cardiomyopathy managed medically. These cases underscore the incremental value of CMR in detecting, characterizing, and monitoring myocardial metastases. Integration of positron emission tomography and CMR may enable earlier diagnosis and inform management decisions. A multidisciplinary approach is essential, as selected patients may benefit from surgical or systemic therapies despite the typically indolent course of cardiac NET metastases.