Carcinoid Heart Disease: Diagnostic Value of Cardiac MRI in a Patient With Metastatic Small‑Intestinal Neuroendocrine Tumor.

Carcinoid heart disease (CHD) is a serious and potentially life‑limiting complication of neuroendocrine tumors (NETs), resulting from prolonged systemic exposure to serotonin and other vasoactive substances, leading to fibrotic valvular degeneration. We report the case of a 71‑year‑old woman with metastatic small‑intestinal NET and associated carcinoid syndrome presenting with progressive exertional intolerance. Transthoracic echocardiography revealed severe tricuspid and moderate pulmonary regurgitation with right‑sided ventricular dilation. Cardiac MRI confirmed regurgitation and right‑heart remodeling consistent with CHD. Teaching point: This case highlights the diagnostic value of multimodal imaging, particularly cardiac MRI, in confirming and characterizing CHD in patients with metastatic NETs.