What are the common symptoms of carcinoid syndrome in dogs and cats?

Common symptoms include loss of appetite, repeated vomiting, weight loss, and changes in energy and activity level; some cases may also show abdominal distension or dark stools. Any abnormalities should be discussed with your vet for further investigation.

How does a vet typically diagnose carcinoids or carcinoid syndrome?

Diagnosis usually involves a combination of blood and biochemistry tests, abdominal imaging (ultrasound or radiographs), and tissue biopsy for histopathological confirmation; advanced imaging (CT/MRI) may be used for comprehensive staging.

What can I prepare at home to help with the diagnosis?

Keep a record of appetite, vomiting frequency and content, stool colour, and recent body weight; also bring a list of current medications and any previous test results so the vet can quickly understand the clinical timeline.

Is carcinoid syndrome contagious or hereditary to other pets?

Carcinoids are neoplastic conditions and are not contagious to other pets; if there is a suspected hereditary predisposition, a vet should assess the medical history and test results. It is advisable to consult your vet about individual risk.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Carcinoid Syndrome in Dogs & Cats: Symptoms, Diagnosis & Care [2025]

Carcinoids are neuroendocrine tumors that can secrete hormones and cause carcinoid syndrome; treatment focuses primarily on surgical resection.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: ACVIM, WSAVA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek Emergency Care Immediately

•Sudden collapse or prolonged unresponsiveness
•Obvious difficulty breathing or open-mouth panting
•Persistent vomiting, inability to eat, and severe lethargy

Schedule a Clinic Visit Soon (within 24–72 hours)

•Noticeably reduced appetite lasting more than two days
•Repeated vomiting with increasing frequency
•Ongoing weight loss or visibly distended abdomen

01What symptoms indicate something is wrong?

Carcinoids and carcinoid syndrome in dogs and cats typically present as non-specific gastrointestinal and systemic signs, which may develop gradually or occur in recurring episodes.

Persistent or intermittent loss of appetite; some pets may refuse food entirely
Repeated vomiting or increased frequency of vomiting
Gradual, unexplained weight loss
Lethargy and noticeably reduced activity levels
Abdominal distension; palpation may suggest ascites or a mass
Dark or tarry stools, which may indicate gastrointestinal bleeding

Seek emergency care immediately if you notice the following symptoms:

⚠️ Sudden collapse or prolonged unresponsiveness
⚠️ Obvious respiratory distress or open-mouth breathing
⚠️ Persistent vomiting with inability to eat and severe lethargy

02How to assess an abnormality at home? Key observations and emergency guidelines

Monitoring and recording specific changes at home helps your vet quickly assess the disease progression and severity.

Track appetite changes and actual food intake at each meal (include date and time)
Record vomiting episodes: frequency, time, contents, and whether blood is present
Weigh weekly or more frequently and track the trend over time
Observe changes in energy level, activity, sleep patterns, and interactive behaviour
Note stool colour and frequency; pay particular attention to dark or bloody stools
If symptoms persist or worsen, contact your vet promptly to arrange an appointment

03How will the vet diagnose this? Common diagnostic tests

In-clinic assessment typically includes a physical examination, blood tests, and imaging to identify the underlying cause and evaluate disease staging.

Thorough physical examination

abdominal palpation, lymph node assessment, and evaluation of surface masses

Complete blood count and biochemistry panel

assess organ function and overall health status

Abdominal ultrasound

identify masses, ascites, or visceral lesions

Radiographs (thoracic and abdominal)

assess for metastasis or structural changes

Tissue biopsy or fine-needle aspirate for histopathological diagnosis

Advanced imaging (CT or MRI) for comprehensive staging when indicated

04How is this condition treated and managed after diagnosis? Medications, dietary adjustments, and care guide

Treatment and monitoring are determined by pathology results and the patient's overall condition; regular follow-up visits and home tracking of side effects are important.

Treatment options depend on tumour type and stage (surgery, medication, or other approaches)
Attend regular follow-up appointments for blood work or imaging as recommended by your vet
Dietary adjustment and weight management are key components of supportive care
Record any treatment side effects, behavioural changes, or changes in appetite at home to assist evaluation
Patients undergoing advanced treatment are advised to be managed by a team experienced in oncology

05What to prepare before the vet visit? Key information to help your vet identify the problem quickly

List the onset date and progression of symptoms (specific dates and changes)

Prepare a log or photos of recent vomiting, bowel movements, and food intake

Bring recent weight records (photos or data)

List all current medications, supplements, and any known allergies

Bring previous test reports or imaging results if available

If possible, book an appointment at a clinic that offers imaging and oncology assessment in advance

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.