A Case of Carcinoid Syndrome Due to Malignant Metastatic Carcinoid Tumor with Carcinoid Heart Disease Involving Four Cardiac Valves

BACKGROUND Carcinoid tumor, benign, low-grade malignant, and high-grade malignant, can be associated with the release of vasoactive substances that cause symptoms including cutaneous flushing, diarrhea, and bronchospasm. In 50-60% of patients with carcinoid syndrome, the vasoactive substances cause fibrosis of the pulmonary and tricuspid heart valves which lead to regurgitation and right-sided heart failure. The right side of the heart is usually affected because monoamine oxidases in the lungs usually inactivate the vasoactive substances. CASE REPORT A 62-year-old woman presented with a four-month history of diarrhea and abdominal discomfort. The patient had bilateral pelvic masses and elevated serum CA125 and an elevated urinary 5-hydroxyindoleacetic acid (5-HIAA). Total abdominal hysterectomy (TAH) and bilateral salpingo-oophorectomy (BSO) identified a primary appendiceal carcinoid tumor with bilateral ovarian metastases. Post-operatively, a computed tomography (CT) scan showed cardiomegaly. Transthoracic echocardiography showed morphologic changes that affected all four heart valves, consistent with carcinoid heart disease but without a patent foramen ovale (PFO). The patient was evaluated for valve replacement surgery, but surgery was not performed due to the degree of heart failure. CONCLUSIONS This report describes a rare case of carcinoid heart disease with involvement of all four cardiac valves, but without the presence of a PFO, possibly due to a large amount of vasoactive substances in the patient's circulation, as supported by the patient's elevated urinary 5-HIAA. This rare presentation highlights the importance of early diagnosis and treatment with tumor resection and, if possible, Cardiac valve replacement to prevent irreversible heart failure.