Intestinal tumor arising from hormone-producing cells in dogs (Neuroendocrine Intestinal Tumor, Apudoma)
- Occurrence: very rare
- Location of disease: Abdomen/pelvis
When to visit the vet?
Non-urgent see a veterinarian within 2–3 days
If the condition worsens / symptoms persist, consult a veterinarian.
Definition
An Apudoma, also known as a neuroendocrine tumor of the intestine, is a rare type of tumor that originates from neuroendocrine cells in a dog’s digestive tract. These cells are responsible for producing hormones and other chemical messengers that regulate various bodily functions.
The most important facts at a glance
Neuroendocrine tumors (NETs) in dogs arise from specialized cells that have both nervous and hormone-producing functions. These cells are found throughout the body, including in the gastrointestinal tract. If these cells multiply uncontrollably, Tumors such as Apudomas can develop. The exact causes are still unclear, but genetic factors and environmental conditions may play a role. Symptoms of these tumors can include Vomiting, Weight loss, loss of appetite, and Diarrhea. Diagnosis is made through a clinical examination, imaging tests such as ultrasound or X-ray, and a biopsy of the tumor tissue. Blood tests can reveal the tumor’s hormonal activity.
Treatment depends on the tumor’s size and location. Surgical removal is often the best option, while chemotherapy or targeted therapies are used when surgery is not possible. Hormonally active tumors can be treated with medications to relieve symptoms. The prognosis varies widely depending on factors such as tumor size and metastasis. Prevention is difficult to define, but a healthy diet and regular veterinary examinations can help detect health problems early. Research focuses on genetic analyses and the development of new diagnostic and treatment methods, including immunotherapies.
Causes
Neuroendocrine tumors (NETs) arise from neuroendocrine cells, which exhibit characteristics of both nerve cells and hormone-producing cells. These cells are present in various organs throughout the body, including the gastrointestinal tract, and play a crucial role in regulating digestion and other physiological processes.
In the intestine, neuroendocrine cells are responsible for releasing hormones such as serotonin and gastrin, which control gastrointestinal motility and gastric acid secretion. If these cells multiply uncontrollably, it can lead to the formation of tumors, known as Apudomas or neuroendocrine tumors.
The exact causes of Apudomas in dogs are not yet fully understood. However, it is believed that genetic factors and environmental conditions may play a role. In some cases, mutations in specific genes responsible for cell growth and cell division can contribute to tumor development.
Other possible causes could include chronic Inflammatory conditions of the intestine or prolonged exposure to certain carcinogens. These can damage cell DNA and increase the risk of tumor formation. Environmental factors such as diet, lifestyle, and exposure to toxins could also influence the development of Apudomas.
Symptoms
Symptoms of a neuroendocrine tumor in a dog’s intestine can vary depending on the tumor’s size and location, as well as the hormone activity of the tumor tissue. The most common symptoms include Vomiting, Diarrhea, and Weight loss. These occur when the tumor disrupts normal intestinal function.
Another common symptom is a bloated abdomen, which can be caused by a buildup of fluid or gas in the intestine as a result of tumor growth. In some cases, constipation may occur if the tumor blocks the intestine.
If the tumor is hormonally active, additional symptoms may occur due to excessive hormone release. These include excessive thirst and frequent urination, Skin changes, and Behavioral changes.
Since these symptoms can also occur with other gastrointestinal diseases, it is important to obtain a comprehensive diagnosis from a veterinarian to determine the exact cause.
Key warning signs include episodic, hormone-driven symptom patterns (neurological with hypoglycemia, gastrointestinal complaints with gastrinoma, cardiovascular complaints with pheochromocytoma) as well as a possible abdominal mass/liver involvement.
Therapy
Treatment of an Apudoma in dogs depends on the tumor’s size, location, and hormonal activity. Surgical removal is often the preferred treatment method, especially if the tumor is localized and operable. The procedure aims to completely remove the tumor and, if necessary, affected surrounding tissue.
In cases where the tumor is inoperable or has already spread, medical therapy with chemotherapy or targeted therapies may be considered. These treatments aim to slow tumor growth and alleviate symptoms.
If the tumor is hormonally active, medications may be used to control hormone production. These can help relieve symptoms caused by the tumor and improve the dog’s quality of life.
The exact treatment strategy should be tailored to the individual dog and requires close collaboration with a veterinary oncologist or internal medicine specialist.
Prognosis and follow-up care
The prognosis for dogs with a neuroendocrine tumor in the intestine varies widely and depends on several factors, including the tumor’s size and location, its hormone activity, and the extent of spread throughout the body. Tumors that are diagnosed early and can be successfully removed surgically have a better prognosis.
However, if the tumor has already metastasized or is inoperable, the prognosis may be less favorable. In such cases, treatment may aim to slow disease progression and maintain the dog’s quality of life.
Long-term survival also depends on how the tumor responds to treatment and the dog’s overall health. Regular follow-up examinations and monitoring are crucial to assess disease progression and adjust treatment if necessary.
Prevention
Since the exact causes for the development of Apudomas in dogs are not fully known, there are no specific prevention measures. However, a healthy diet and regular veterinary care can help promote the dog’s general well-being and detect potential health problems early.
Regular check-ups and preventive examinations can help detect changes in the dog’s health early and enable timely interventional measures. This can increase the chances of successful treatment and a better prognosis.
Avoiding exposure to known carcinogens and providing a clean, safe environment can also help reduce the risk of tumor development. A balanced diet with high-quality nutrients can strengthen the immune system and support the dog’s overall health.
Outlook on current research
Research into neuroendocrine tumors (NETs) in dogs, especially in the intestinal area, is an evolving field focused on understanding the underlying biological mechanisms. A key research focus is the genetic characterization of these Tumors. Through genetic analyses, scientists aim to identify specific mutations or genetic markers that contribute to tumor development. These findings could lead to more precise diagnostic methods and more targeted therapies in the future.
Another area of research looks at the role of the tumor microenvironment, including interactions between tumor cells and surrounding tissue. Researchers are investigating how these interactions influence tumor growth and metastasis. A deeper understanding of these processes could enable new therapeutic approaches aimed at modifying the tumor environment and inhibiting tumor growth.
In addition, the development of new diagnostic imaging techniques is being advanced to enable earlier and more accurate detection of NETs. Technologies such as PET-CT (positron emission tomography combined with computed tomography) are being further developed to improve the detection of early-stage tumors. Such advances could significantly improve the prognosis for affected dogs by enabling earlier intervention.
With regard to the treatment of neuroendocrine tumors in dogs, intensive work is underway to develop and test new drug therapies. This includes targeted therapies that focus on the molecular characteristics of tumor cells. Such therapies could reduce side effect compared to conventional chemotherapy and improve the quality of life of affected dogs.
Finally, researchers are also investigating the use of immunotherapies in dogs with NETs. These treatments aim to activate the dog’s immune system to fight tumor cells more effectively. While these approaches are still in the early stages of research, initial results are promising for improving treatment options for dogs with neuroendocrine tumors.
Frequently Asked Questions (FAQs)
1. What is a neuroendocrine tumor in dogs?
2. What symptoms do dogs with a neuroendocrine tumor show?
3. How is a neuroendocrine tumor diagnosed in dogs?
4. What treatment options are available for dogs with neuroendocrine tumors?
5. What is the prognosis for dogs with neuroendocrine tumors?
6. Can neuroendocrine tumors in dogs be prevented?
7. Are certain dog breeds more susceptible to neuroendocrine tumors?
8. What role do hormones play in neuroendocrine tumors?
9. How does the tumor’s location affect symptoms and treatment?
10. Are there experimental treatments for neuroendocrine tumors in dogs?
Literature
- Champion, C. P., Miller, A. D., Parry, S., & Demeter, E. A. (2025). Immunohistochemical and histomorphologic characterization of canine neoplasms of the disseminated neuroendocrine system. Veterinary Pathology, 62(4). https://doi.org/10.1177/03009858251324652
- Patnaik, A. K., Hurvitz, A. I., & Johnson, G. F. (1980). Canine intestinal adenocarcinoma and carcinoid. Veterinary Pathology, 17(2), 149–163. https://doi.org/10.1177/030098588001700204
- Sykes, G. P., & Cooper, B. J. (1982). Canine intestinal carcinoids. Veterinary Pathology, 19(2), 120–131. https://doi.org/10.1177/030098588201900203
- Tappin, S., Brown, P., & Ferasin, L. (2008). An intestinal neuroendocrine tumour associated with paroxysmal ventricular tachycardia and melaena in a 10-year-old boxer. Journal of Small Animal Practice, 49(1), 33–37. https://doi.org/10.1111/j.1748-5827.2007.00389.x
- Giles, R. C., Jr., Hildebrandt, P. K., & Montgomery, C. A., Jr. (1974). Carcinoid tumor in the small intestine of a dog. Veterinary Pathology, 11(4), 340–349. https://doi.org/10.1177/030098587401100406
- Slodki, S., & Bogucka, J. (2021). Neuroendocrine tumor of the large intestine in a dog. Kafkas Universitesi Veteriner Fakultesi Dergisi, 27(2), 259–264. https://doi.org/10.9775/kvfd.2020.24929
- O’Brien, K. M., Bankoff, B. J., Rosenstein, P. K., Clendaniel, D. C., Sánchez, M. D., & Durham, A. C. (2021). Clinical, histopathologic, and immunohistochemical features of 13 cases of canine gallbladder neuroendocrine carcinoma. Journal of Veterinary Diagnostic Investigation, 33(2), 294–299. https://doi.org/10.1177/1040638720978172
- Herbach, N., Unterer, S., & Hermanns, W. (2012). Gastric neuroendocrine carcinoma in a dog. Open Journal of Pathology, 2(4), 162–165. https://doi.org/10.4236/ojpathology.2012.24031
- Champion, C. P., Miller, A. D., Parry, S., & Demeter, E. A. (2025). Immunohistochemical and histomorphologic characterization of canine neoplasms of the disseminated neuroendocrine system. Veterinary Pathology, 62(4). https://doi.org/10.1177/03009858251324652
- Patnaik, A. K., Hurvitz, A. I., & Johnson, G. F. (1980). Canine intestinal adenocarcinoma and carcinoid. Veterinary Pathology, 17(2), 149–163. https://doi.org/10.1177/030098588001700204
- Sykes, G. P., & Cooper, B. J. (1982). Canine intestinal carcinoids. Veterinary Pathology, 19(2), 120–131. https://doi.org/10.1177/030098588201900203
- Tappin, S., Brown, P., & Ferasin, L. (2008). An intestinal neuroendocrine tumour associated with paroxysmal ventricular tachycardia and melaena in a 10-year-old boxer. Journal of Small Animal Practice, 49(1), 33–37. https://doi.org/10.1111/j.1748-5827.2007.00389.x
- Giles, R. C., Jr., Hildebrandt, P. K., & Montgomery, C. A., Jr. (1974). Carcinoid tumor in the small intestine of a dog. Veterinary Pathology, 11(4), 340–349. https://doi.org/10.1177/030098587401100406
- Slodki, S., & Bogucka, J. (2021). Neuroendocrine tumor of the large intestine in a dog. Kafkas Universitesi Veteriner Fakultesi Dergisi, 27(2), 259–264. https://doi.org/10.9775/kvfd.2020.24929
- O’Brien, K. M., Bankoff, B. J., Rosenstein, P. K., Clendaniel, D. C., Sánchez, M. D., & Durham, A. C. (2021). Clinical, histopathologic, and immunohistochemical features of 13 cases of canine gallbladder neuroendocrine carcinoma. Journal of Veterinary Diagnostic Investigation, 33(2), 294–299. https://doi.org/10.1177/1040638720978172
- Herbach, N., Unterer, S., & Hermanns, W. (2012). Gastric neuroendocrine carcinoma in a dog. Open Journal of Pathology, 2(4), 162–165. https://doi.org/10.4236/ojpathology.2012.24031