Gastrointestinal · Year 2 · from Gastrointestinal
Case 2: Carcinoid Syndrome
Patient Presentation
Demographics: 58-year-old female
Chief Complaint: Episodic flushing, diarrhea, and wheezing for 6 months
History of Present Illness: The patient experiences sudden episodes of facial and upper body flushing lasting several minutes, often triggered by alcohol or stress. She has 5-6 watery stools daily. She has developed new-onset wheezing without prior asthma history. She reports fatigue and has noticed ankle swelling. She has lost 10 pounds.
Past Medical History: None significant
Social History: Occasional wine (now avoids due to flushing)
Physical Examination
- Vital Signs: BP 110/70 mmHg, HR 96 bpm, BMI 24
- General: Female with visible facial telangiectasias
- Cardiovascular: Systolic murmur at left sternal border (tricuspid area); JVD present
- Lungs: Diffuse expiratory wheezes
- Abdomen: Hepatomegaly (liver edge 5 cm below costal margin), multiple firm nodules palpable
- Extremities: 2+ pitting edema bilaterally
Workup and Results
- 24-hour Urine 5-HIAA: 85 mg (markedly elevated, normal <6 mg)
- Serum Chromogranin A: 1,250 ng/mL (elevated)
- CT Abdomen: 2.5 cm enhancing mass in the ileum; multiple hypervascular liver metastases
- Ga-68 DOTATATE PET/CT: Intense uptake in ileal mass and liver lesions (somatostatin receptor positive)
- Echocardiogram: Thickened, restricted tricuspid valve with severe regurgitation; mild pulmonic stenosis
CT scan demonstrating multiple hypervascular hepatic metastases (arrows) from a small bowel carcinoid tumor. Liver metastases allow serotonin to bypass hepatic metabolism and cause carcinoid syndrome.
Image Source: Case courtesy of Radiopaedia.org
Diagnosis
Carcinoid Syndrome from Metastatic Small Bowel Neuroendocrine Tumor with Carcinoid Heart Disease
Clinical Correlation
Small bowel neuroendocrine tumors (carcinoids) arise from enterochromaffin cells and produce serotonin. Carcinoid syndrome only develops when tumor products reach systemic circulation, which typically requires liver metastases (bypassing hepatic first-pass metabolism). Serotonin causes: (1) flushing - vasoactive effects; (2) diarrhea - stimulation of intestinal motility and secretion; (3) wheezing - bronchoconstriction. Carcinoid heart disease affects right-sided valves (tricuspid, pulmonic) because serotonin is metabolized by the lungs before reaching the left heart. The diagnosis is confirmed by elevated urinary 5-HIAA (serotonin metabolite) and chromogranin A.
Treatment
- Somatostatin analog: octreotide LAR 30 mg IM monthly (controls symptoms, may slow tumor growth)
- Telotristat (tryptophan hydroxylase inhibitor) for diarrhea refractory to octreotide
- Peptide receptor radionuclide therapy (177Lu-DOTATATE) for somatostatin receptor-positive metastatic disease
- Surgical debulking of liver metastases if feasible
- Cardiology evaluation for carcinoid heart disease; consider valve surgery if severe
- Perioperative octreotide to prevent carcinoid crisis during any procedures