A rare case of carcinoid heart disease caused by neuroendocrine tumor of unknown primary site

Abstract

Carcinoid syndrome is caused by chronic serotonin excess due to liver metastases of neuroendocrine tumours. Episodic flushing, bronchospasm, diarrhea and dyspnea are frequent among patients with carcinoid disease. Carcinoid heart disease affects the right heart in 95% of cases resulting in ventricular failure, tricuspid and pulmonary valve disease and may be fatal. Octreotide blocks hormonal release and can reduce the risk of developing carcinoid heart disease. We report a case of a 72-year old woman with metastasized neuroendocrine tumor of unknown primary site (NET-CUP), who was admitted to internal medicine for acute renal failure, flush, diarrhea, and dyspnea occurring after a third 90Y- DOTATOC treatment course. Urinary 5-HIAA levels were elevated (> 35 mg/24h) and chromogranin A levels were high at 7126 µg/l. ECG showed sinus tachycardia, low voltage QRS and right bundle block suggesting right heart failure. The transthoracic echocardiography revealed maximal tricuspid regurgitation, thickening and retraction of tricuspid leaflets. Consequently, the right ventricle was enlarged (RA 62 mm, RV 50 mm) and septal motility was abnormal. Trans-esophageal echocardiography revealed pulmonary stenosis I°. The findings represented an extreme example of carcinoid heart disease, which had not been diagnosed before in the patient. Due to advanced tricuspidal insufficiency balloon valvuloplasty was not an option and the patient declined cardiac valve surgery. Conservative therapy with loop diuretics, beta blockers, balanced fluid intake and short-acting somatostatin analogues relieved symptoms.