Multivalvular Cardiac Involvement from Giant Hepatic Metastases of an Ileal Neuroendocrine Tumor.

Intestinal neuroendocrine tumors (NETs) are rare, slow-growing neoplasms arising from enterochromaffin cells, capable of secreting vasoactive substances that may cause carcinoid syndrome (CS) and clinically significant valvular heart disease. These tumors are often diagnosed at advanced stages due to nonspecific gastrointestinal symptoms, and distant metastases, particularly to the liver and lymph nodes, are common at presentation. Hormonal dysregulation can lead to chronic diarrhea, flushing, and bronchospasm, while carcinoid heart disease (CHD) contributes substantially to morbidity and mortality, typically affecting right-sided valves, with left-sided involvement being uncommon and more frequently associated with intracardiac shunts than exceptionally high serotonin exposure. Recent advances in management emphasize a multidisciplinary approach integrating systemic therapy, surgery, and targeted radionuclide treatment. Somatostatin analog therapy remains the cornerstone for controlling hormonal symptoms and slowing tumor progression. Aggressive cytoreductive surgery to achieve hormonal stabilization prior to surgical valve replacement has been associated with improved survival, symptomatic relief, and cardiac function. Targeted peptide receptor radionuclide therapy provides additional treatment for residual or metastatic disease, enhancing biochemical and radiological control. We report the case of a 61-year-old woman with chronic diarrhea, weight loss, and recurrent flushing, diagnosed with a well-differentiated ileal NET with extensive hepatic metastases and severe right-sided valvular disease with mild left-sided involvement. She underwent somatostatin analog therapy to control hormonal symptoms, cytoreductive surgery, and surgical replacement of the pulmonary and tricuspid valves. Subsequent targeted peptide receptor radionuclide therapy further reduced tumor burden and stabilized biochemical markers. This combined multimodal strategy resulted in sustained clinical improvement, normalization of neuroendocrine markers, and long-term oncologic stability, as the patient remains asymptomatic and oncologically stable after four years of follow-up from initial presentation. This case highlights the importance of early recognition, comprehensive evaluation, and a multidisciplinary strategy in advanced NETs. Coordinated care integrating endocrinology, oncology, cardiology, nuclear medicine, and surgery can significantly improve survival, hormonal control, and quality of life in patients with complex metastatic disease.