🔍 What Are Carcinoid (Neuroendocrine) Tumors?

Carcinoids—aka neuroendocrine tumors—are rare, slow-growing cancers arising from hormone-secreting cells in the GI tract, liver, stomach, pancreas, or skin :contentReference[oaicite:3]{index=3}. In cats, they've been documented in the duodenum, liver, gallbladder, and stomach :contentReference[oaicite:4]{index=4}.

🐾 Who’s at Risk?

Most cases involve middle-aged to older cats (7+ years), with no strong breed predilection :contentReference[oaicite:5]{index=5}. The tumors are rare, with very few documented feline cases.

⚠️ Common Signs by Location

• Gastrointestinal/Gastric: chronic vomiting, diarrhea (sometimes bloody), weight loss; duodenal carcinoid may cause GI bleeding and anemia :contentReference[oaicite:6]{index=6}.
• Hepatic: in liver, signs include poor appetite, vomiting, weight loss, enlarged liver; cats may deteriorate rapidly :contentReference[oaicite:7]{index=7}.
• Gallbladder: extremely rare; may present with cholestasis or incidental imaging finding :contentReference[oaicite:8]{index=8}.
• Intestinal obstruction: larger tumors may block GI tract :contentReference[oaicite:9]{index=9}.

🧬 How They Work (Pathophysiology)

Derived from neuroendocrine cells, these tumors might produce hormones/amine substances. In humans, this leads to carcinoid syndrome. In cats, similar paraneoplastic behavior is rare, though gastrin-producing hepatic tumors have been reported :contentReference[oaicite:10]{index=10}.

🔬 Diagnosis: Step-by-Step

• History & physical: note GI, hepatic, or systemic signs.
• Blood tests: CBC, chemistry; may show liver enzyme elevations or anemia :contentReference[oaicite:11]{index=11}.
• Imaging: Ultrasound and CT/MRI are crucial for detecting masses in GI or liver :contentReference[oaicite:12]{index=12}.
• Endoscopy: Helps biopsy gastric or duodenal tumors :contentReference[oaicite:13]{index=13}.
• Fine-needle aspiration/biopsy: Required for definitive histology—neuroendocrine appearance, rosette/cord structures :contentReference[oaicite:14]{index=14}.
• Immunohistochemistry: Chromogranin A, synaptophysin positivity confirms neuroendocrine origin; gastrin-marker identifies functional gastrinoma :contentReference[oaicite:15]{index=15}.

✂️ Treatment & Management

• Surgery: Preferred for solitary or accessible tumors—partial gastrectomy, hepatic lobectomy, etc.; provides best chance :contentReference[oaicite:16]{index=16}.
• Medical management: For functional tumors (e.g., gastrin-producing), proton pump inhibitors or somatostatin analogues may help :contentReference[oaicite:17]{index=17}.
• Palliation: Supportive therapy—fluids, appetite stimulants, anti-nausea medications.
• Prognosis: Varies—gut carcinoids may recur but often slow-growing; hepatic cases have poorer outcomes, often <6 months survival :contentReference[oaicite:18]{index=18}.

📅 Prognosis & Follow-Up

• GI carcinoids: Guarded–fair if fully excised.
• Hepatic neuroendocrine carcinomas: Poor—rapid decline common despite treatment :contentReference[oaicite:19]{index=19}.
• Metastasis: Common at diagnosis; follow-up imaging every 3–6 months advised.

🐾 Supportive Home Care

• Keep cats comfortable with soft diets and gentle feeding.
• Monitor GI signs—vomiting, appetite, litter habits.
• Maintain hydration—wet food, fresh water.
• Use Ask A Vet app for round-the-clock advice.
• Reduce stress with calming Woopf & Purrz aids.

📝 Summary Table