Diagnostic Dilemma of a Neuroendocrine Tumour Complicated by Simultaneous Retroperitoneal Fibrosis and Carcinoid Heart Disease in a Perimenopausal Woman

Carcinoid tumours are rare, slow-growing neuroendocrine neoplasms that often remain asymptomatic until metastatic spread or the development of carcinoid syndrome. Carcinoid syndrome is characterised by flushing, diarrhoea, and bronchospasm due to the secretion of vasoactive hormones. These tumours commonly arise in the gastrointestinal tract but can also occur in other organs, namely, the lungs, genitourinary tract, and pancreas. Retroperitoneal fibrosis (RPF), a rare inflammatory disease, involves chronic inflammation leading to fibrous scarring and compression of surrounding structures like the ureters and blood vessels. Carcinoid heart disease secondary to fibrous valve thickening can also occur and causes high morbidity and mortality. This case report highlights a 52-year-old woman who developed a rare complication of RPF along with carcinoid heart disease secondary to a carcinoid tumour. Her symptoms, initially misdiagnosed as menopausal, included a four-year history of diarrhoea, uncontrolled hypertension, and flushing. She was admitted with abdominal pain, acute kidney injury, and bilateral hydronephrosis. Imaging and biochemical tests revealed a primary ileocecal carcinoid tumour with hepatic metastases, RPF causing ureteric obstruction, and elevated chromogranin A/B and urinary 5-hydroxyindoleacetic acid (5-HIAA) levels. Cardiac involvement included severe tricuspid regurgitation, pulmonary hypertension, and impaired left ventricular function, consistent with carcinoid heart disease. Management involved nephrostomy placement following failed bilateral ureteric stenting, octreotide infusions to prevent carcinoid crisis, and symptomatic control with lanreotide. The patient continues to receive multidisciplinary care from cardiology, urology, and oncology. This case underscores the complexity of diagnosing and managing carcinoid tumours with atypical presentations and rare complications like RPF.