A silent tumor, a loud valve: carcinoid heart disease as the first manifestation of a pelvic neuroendocrine tumor.

Carcinoid heart disease (CaHD) is a well-recognized complication of functional neuroendocrine tumors (NETs), typically occurring in the presence of hepatic metastases that permit vasoactive substances to reach the systemic circulation. Its occurrence in the absence of liver involvement is uncommon and may delay diagnosis. We report a 46-year-old woman who was incidentally found to have severe tricuspid regurgitation during preoperative evaluation for uterine fibroids. Further evaluation revealed elevated 24-hour urinary 5-hydroxyindoleacetic acid and markedly increased chromogranin A levels, raising suspicion of a functional NET. Imaging identified a large somatostatin receptor-avid pelvic mass without evidence of hepatic or distant metastasis. The patient underwent successful surgical excision following perioperative octreotide infusion, and histopathology confirmed a Grade 1 well-differentiated neuroendocrine tumor arising from the mesosalpinx/peritoneal region suggestive of a primary extraintestinal neuroendocrine tumor. Postoperatively, she demonstrated biochemical improvement and clinical stabilization on somatostatin analog therapy; however, severe tricuspid regurgitation persisted. This case highlights an unusual presentation of CaHD in the absence of hepatic metastasis and underscores the importance of considering neuroendocrine tumors in patients with unexplained right-sided valvular heart disease.