Malignant Adrenal Gland Tumor in Dogs (Adrenocortical Carcinoma)
- 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 adrenocortical carcinoma is a rare, malignant tumor that originates in the adrenal cortex of dogs, affecting the hormone-producing tissue of these glands.
BASICS and CAUSES:
The adrenal glands are small, triangular glands located above the kidneys. They consist of two main parts: the inner medulla and the outer cortex. The cortex is responsible for producing vital hormones such as cortisol, aldosterone, and sex hormones. These hormones regulate numerous bodily functions, including metabolism, blood pressure, and stress responses.
In adrenocortical carcinoma, cancer cells grow uncontrollably in the adrenal cortex. This can lead to overproduction or, less commonly, underproduction of these hormones, causing various health problems. The exact causes for the development of these tumors are not fully understood; however, genetic factors and possibly environmental factors play a role.
Genetic predispositions might play a role in certain dog breeds, although no specific breed has been clearly identified. There are indications that chronic stress and environmental toxins could increase the risk, but further research is needed to definitively confirm these factors.
The most important facts at a glance
Adrenocortical carcinoma is a rare but aggressive tumor of the adrenal cortex in dogs, which is often hormonally active and clinically associated with Cushing’s syndrome. The primary therapy consists of surgical removal, which requires precise diagnostics and a specialized surgical technique. In inoperable cases, medicinal control of hormone production can be carried out. The prognosis depends heavily on metastasis and resectability (how well a tumor can be surgically removed).
Causes
The exact causes are unknown, but genetic factors may play a role.
- Hormonal Dysregulation: A malignant tumor in the adrenal cortex can lead to excessive cortisol production. Rarer variants produce aldosterone or sex hormones.
- Genetic Factors: While there is no clearly defined breed predisposition for adrenocortical carcinomas in dogs, a familial accumulation is discussed in individual cases. In human medicine, mutations in tumor suppressor genes (e.g., TP53) are known. Their transferability to veterinary medicine is being researched.
- Breed Prevalence: Certain dog breeds like Poodles, Dachshunds, and Beagles more frequently show Cushing’s syndrome – however, this is mostly pituitary-dependent. An adrenocortical carcinoma as a cause is possible, but overall less common.
The exact pathogenesis of adrenocortical carcinomas is not fully understood. Genetic factors, chronic hormonal dysregulation, and environmental carcinogens are suspected to promote their development. In human medicine, a familial accumulation within the framework of tumor syndromes is described, but this has not yet been proven in dogs. Hormonally active carcinomas may be influenced by autocrine growth stimulation. Adrenocortical adenomas can become malignant, but a transition into a carcinoma is rarely documented. A connection with previous glucocorticoid therapy is not clearly established but is the subject of ongoing research.
Symptoms
Symptoms of an adrenocortical carcinoma can be diverse and often depend on whether the tumor is hormonally active. Owners frequently report increased thirst and increased urination in their dogs. This symptom is often accompanied by a change in appetite, which can be either increased or decreased.
Dogs may also show signs of Muscle weakness or wasting, especially in the hind legs. Furthermore, changes in coat or skin problems may occur, such as Hair loss and thin, sensitive skin. In some cases, dogs may also experience Weight gain or develop a bloated abdomen, which can indicate an enlarged liver or spleen.
In advanced cases or if the tumor has metastasized, general weakness, lethargy, and in some cases, neurological symptoms such as Behavioral changes or Convulsions may occur. Since the symptoms are so varied, an accurate diagnosis is crucial.
In summary:
A combination of thirst and increased urination (PU, PD) + increased appetite (polyphagia) + skin/muscle changes suggests Cushing’s syndrome.
Therapy
The primary treatment for an adrenocortical carcinoma consists of surgical removal of the tumor, provided this is possible. The operation can be complicated, especially if the tumor is large or has spread to surrounding tissue. In some cases, complete removal is not possible, and palliative treatment is considered.
After surgery, chemotherapy or radiation therapy may be used to fight remaining cancer cells. The choice of therapy often depends on the size of the tumor, its location, and the presence of metastasis. Hormone therapies can also be used to alleviate symptoms, especially if the tumor was hormonally active.
Medications to control hormone production and alleviate symptoms can also be part of the treatment. Close monitoring of the dog through regular veterinary visits is crucial to assess the success of the therapy and to detect possible complications early.
Prognosis and follow-up care
The prognosis for dogs with an adrenocortical carcinoma varies greatly and depends on several factors, including the size of the tumor, the presence of metastasis, and the treatment results. If the tumor is detected early and completely removed, the prognosis can be relatively favorable.
In cases where the tumor has metastasized or cannot be completely removed, the prognosis is generally poorer. Life expectancy can then be limited to months, depending on the aggressiveness of the tumor and the chosen treatment strategy.
Early diagnosis and treatment are crucial to improve the dog’s quality of life and optimize the prognosis. Regular follow-up examinations are necessary to detect tumor recurrence or the appearance of metastases early.
Prevention
Adrenocortical carcinoma cannot be reliably prevented, but early detection significantly improves the prognosis. Regular preventive examinations with blood and hormone profiles, especially in older dogs, are recommended. Symptoms such as increased drinking, hair loss, muscle wasting, or unusual weight gain should be taken seriously. Avoiding unnecessary hormonal medications can reduce the risk of hormone-related changes. In genetically predisposed breeds, close monitoring is advisable. Ultrasound examinations of the abdomen can also make changes to the adrenal glands visible at an early stage.
Outlook on current research
Adrenocortical carcinoma in dogs is a rare but serious condition affecting the adrenal cortex. The adrenal cortex is responsible for producing vital hormones such as cortisol. Current research is investigating how genetic factors may contribute to the development of these tumors. Researchers are analyzing genetic markers that occur more frequently in dogs with this disease to gain a better understanding of the causes and possible hereditary components.
Another research focus lies in improving diagnostic methods. Currently, imaging procedures such as ultrasound and CT are used to localize and assess tumors. New techniques under development could improve the accuracy and early measurement of the diagnosis. Research into the development of biomarkers that can be detected in the blood is particularly promising, as they could enable a non-invasive diagnosis.
Treatment options for adrenocortical carcinomas are also an active field of research. Surgical interventions to remove the affected adrenal glands are currently the most common form of therapy. Researchers are working to optimize surgical techniques to reduce the risk of complications and shorten recovery time. Furthermore, the effectiveness of chemotherapy and radiation therapy as supplementary treatment methods is being investigated. New drugs that specifically target the molecular properties of tumor cells are also being tested in preclinical and clinical studies.
Another important aspect of research is understanding disease progression and the factors that influence survival. Long-term studies on affected dogs help to document the natural course of the disease and evaluate the effects of different treatment strategies on the dogs’ quality of life. These studies provide valuable information that can help develop personalized treatment plans tailored to the individual needs of each dog.
In summary, research on adrenocortical carcinoma in dogs aims to deepen the understanding of the genetic and molecular basis of the disease, improve diagnosis and treatment options, and ultimately improve the prognosis and quality of life of affected dogs. Advances in research could also highlight potential parallels to the treatment of this disease in humans, which could advance knowledge and therapies in both areas.
Frequently Asked Questions (FAQs)
1. What is an adrenocortical carcinoma?
2. What symptoms do dogs with an adrenocortical carcinoma show?
3. How is an adrenocortical carcinoma diagnosed?
4. What treatment options are available for dogs with this condition?
5. What is the prognosis for dogs with an adrenocortical carcinoma?
6. Can adrenocortical carcinoma in dogs be inherited?
7. Are certain dog breeds more susceptible to this condition?
8. How can I help my dog recover after surgery?
9. Are there ways to reduce the risk of an adrenocortical carcinoma?
10. How does an adrenocortical carcinoma affect my dog's quality of life?
Literature
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- Snell, W. L., Berger, A. C., Spoldi, E., Dark, M. J., Hurley, M. E., Suero, M. M., Farina, L. L., de Mello Souza, C. H., Bertran, J., & Maxwell, E. A. (2025). Preoperative computed tomography features as predictors of malignancy and survival in canine adrenal tumours. Veterinary and Comparative Oncology, 23(4), 589–596. https://doi.org/10.1111/vco.70011
- Fontes, G. S., Piegols, H. J., Lapsley, J. M., Bracha, S., & Selmic, L. E. (2024). Outcome in dogs with invasive adrenal gland tumors that did not pursue adrenalectomy. Journal of the American Veterinary Medical Association, 262(7), 1–5. https://doi.org/10.2460/javma.23.12.0689
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- van Bokhorst, K. L., Galac, S., Kooistra, H. S., de Grauw, J. C., Teske, E., Grinwis, G. C. M., & van Nimwegen, S. A. (2023). Laparoscopic vs. open adrenalectomy: Perioperative data and survival analysis in 70 dogs with an adrenal tumor. Frontiers in Veterinary Science, 10, Article 1156801. https://doi.org/10.3389/fvets.2023.1156801
- Pey, P., Specchi, S., Rossi, F., Diana, A., Drudi, I., Zwingenberger, A. L., Mayhew, P. D., Pisoni, L., Mari, D., & Nicoli, S. (2022). Prediction of vascular invasion using a 7-point scale computed tomography grading system in adrenal tumors in dogs. Journal of Veterinary Internal Medicine, 36(2), 713–725. https://doi.org/10.1111/jvim.16371
- Sanders, K., Cirkel, K., Grinwis, G. C. M., Teske, E., van Nimwegen, S. A., Mol, J. A., Hesselink, J. W., Kooistra, H. S., & Galac, S. (2019). The Utrecht Score: A novel histopathological scoring system to assess the prognosis of dogs with cortisol-secreting adrenocortical tumours. Veterinary and Comparative Oncology, 17(3), 329–337. https://doi.org/10.1111/vco.12474
- Yoshida, O., Kutara, K., Seki, M., Ishigaki, K., Teshima, K., Ishikawa, C., Iida, G., Edamura, K., Kagawa, Y., & Asano, K. (2016). Preoperative differential diagnosis of canine adrenal tumors using triple-phase helical computed tomography. Veterinary Surgery, 45(4), 427–435. https://doi.org/10.1111/vsu.12462
- Frankot, J. L., Behrend, E. N., Sebestyen, P., & Powers, B. E. (2012). Adrenocortical carcinoma in a dog with incomplete excision managed long-term with metastasectomy alone. Journal of the American Animal Hospital Association, 48(6), 417–423. https://doi.org/10.5326/JAAHA-MS-5800
- Reusch, C. E., & Feldman, E. C. (1991). Canine hyperadrenocorticism due to adrenocortical neoplasia: Pretreatment evaluation of 41 dogs. Journal of Veterinary Internal Medicine, 5(1), 3–10. https://doi.org/10.1111/j.1939-1676.1991.tb03101.x