Hemangiosarcoma in Dogs: Types, Symptoms, and Diagnosis

Hemangiosarcoma in dogs is a malignant tumor originating from the endothelial cells lining the blood vessels. Hemangiosarcoma is an aggressive cancer that develops in the spleen, liver, and heart and is known for its rapid progression and poor prognosis. 

The types of hemangiosarcoma are splenic, cardiac, and cutaneous. The cause of each hemangiosarcoma in dogs is not fully understood, but genetic predisposition, environmental factors, and exposure to certain chemicals are believed to contribute. 

Symptoms of hemangiosarcoma vary depending on the tumor's location and include lethargy, weight loss, pale gums, abdominal swelling, and sudden collapse due to internal bleeding. 

Hemangiosarcoma in dogs is diagnosed through a combination of imaging techniques, such as ultrasound or X-rays, blood tests, and biopsy of the affected tissue.

Treatment options for hemangiosarcoma in dogs involve surgery to remove the tumor, chemotherapy to target any remaining cancer cells, and supportive care to manage symptoms and improve quality of life.

What is hemangiosarcoma in dogs?

Hemangiosarcoma in dogs is a highly aggressive and malignant cancer that originates from the endothelial cells lining blood vessels, affecting organs such as the spleen, heart, and liver. Hemangiosarcoma spreads rapidly and causes sudden internal bleeding, leading to life-threatening situations. 

The cause of hemangiosarcoma dog diagnosis is unknown, but genetic and environmental factors are purported to contribute to its development. Hemangiosarcoma dog is diagnosed as a type of cancer in dogs middle-aged to older and rapidly metastasizes to other body parts.

What are other terms for hemangiosarcoma in dogs?

The other terms for hemangiosarcoma in dogs are malignant hemangioendothelioma, angiosarcoma, and visceral vascular tumor. These terms denote the benign or aggressive nature of the disease.

Hemangiosarcoma and malignant hemangioendothelioma are specific terms for aggressive vascular cancer in dogs. Angiosarcoma is a broader term for similar cancers in various species. Visceral vascular tumor is an even broader term that includes both benign and malignant vascular tumors in internal organs.

Why is hemangiosarcoma often called a "silent" disease?

Hemangiosarcoma is often called a “silent” disease because it presents no clinical symptoms until the tumor reaches an advanced stage or causes sudden internal bleeding. “Hemangiosarcoma, a devastating cancer, often has no apparent symptoms in early stages and becomes apparent due to hemorrhagic events,” according to the study by Tinsley, A. titled “Canine Hemangiosarcoma: A Certainly Less Than Ideal, Very Ugly Cancer,” 2020.

The stealthy progression makes early detection difficult. Cutaneous hemangiosarcoma tumors on the skin are more noticeable, but internal hemangiosarcomas in the spleen or liver go undetected until they cause sudden and severe health crises.

How does hemangiosarcoma develop in dogs?

Hemangiosarcoma develops in dogs when abnormal endothelial cells proliferate uncontrollably, forming malignant tumors in the lining of blood vessels. The occurrence is due to genetic mutations, such as alterations in the TP53 gene. Dogs over ten years are more likely to develop hemangiosarcoma.

Gene mutations, like TP53, disrupt the cell's ability to control growth and division. The regulation loss leads to the cells dividing and growing uncontrollably, forming tumors. Uncontrolled cell growth results in abnormal blood vessels that are fragile and prone to bleeding.

How common is hemangiosarcoma in dogs?

Hemangiosarcoma is relatively common in dogs. The disease accounts for approximately 5-7% of all canine cancers. Older dogs and genetically predisposed breeds like Golden Retrievers and German Shepherds are more likely to contract hemangiosarcoma. “In this clinical population of dogs, hemangiosarcoma had a higher prevalence (92.6%) than in other studies,” according to the study by Hammond, T., & Pesillo‐Crosby, S. titled “Prevalence of hemangiosarcoma in anemic dogs with a splenic mass and hemoperitoneum requiring a transfusion: 71 cases (2003-2005),” 2008. The disease is relatively rare in cats and puppies.

What are the common types of hemangiosarcoma in dogs?

The common types of hemangiosarcoma in dogs are listed below.

• Splenic Hemangiosarcoma: Splenic is the most common type, causing abdominal swelling, lethargy, and sudden collapse due to internal bleeding.
• Cardiac Hemangiosarcoma: Cardiac arises in the heart, particularly in the right atrium, and leads to heart failure, arrhythmias, and pericardial effusion (fluid around the heart).
• Dermal (Cutaneous) Hemangiosarcoma: Dermal occurs on the skin and is linked to sun exposure, appearing as red or black growths on the skin, which ulcerate and bleed.
• Hepatic Hemangiosarcoma: Hepatic develops in the liver, causing abdominal distension, jaundice, and lethargy due to liver dysfunction and internal bleeding.

1. Splenic Hemangiosarcoma

Splenic hemangiosarcoma is the most common type of hemangiosarcoma in dogs, originating in the spleen and leading to internal bleeding and sudden collapse.

Dogs affected by splenic hemangiosarcoma initially display nonspecific symptoms such as lethargy, decreased appetite, and weight loss. Advanced symptoms include abdominal distension, weakness, and pale gums due to anemia. 

Treatment options for splenic hemangiosarcoma involve surgical removal of the affected spleen, chemotherapy, and radiation therapy to target any remaining cancer cells in some cases.

2. Cardiac Hemangiosarcoma

Cardiac hemangiosarcoma affects the heart, resulting in heart murmurs, arrhythmias, and congestive heart failure due to tumor interference with normal cardiac function.

The aggressive cancer originates in the heart’s blood vessels of the heart, leading to malignant tumors within the cardiac tissue. The tumors are notorious for their ability to rupture unexpectedly, causing catastrophic internal bleeding. 

Cardiac hemangiosarcoma impairs the heart's ability to pump blood effectively, resulting in reduced circulation and oxygen delivery to vital organs. 

3. Cutaneous Hemangiosarcoma

Cutaneous hemangiosarcoma develops in the skin and is linked to exposure to ultraviolet (UV) light, presenting as red or black skin lesions. The cancer progresses by spreading to nearby tissues and lymph nodes. 

Cutaneous hemangiosarcoma dog cases manifest on the skin's surface, unlike internal hemangiosarcoma, which affects organs like the liver and spleen. Lesions on areas frequently exposed to sunlight, such as the head, face, or limbs, are affected. 

Diagnosis of cutaneous hemangiosarcoma involves a biopsy to confirm the presence of malignant cells.

Which breeds are more prone to developing hemangiosarcoma?

The dog breeds that are more prone to developing hemangiosarcoma are listed below.

• German Shepherds: German Shepherds have a higher genetic predisposition to hemangiosarcoma, particularly in the spleen and heart.
• Golden Retrievers: Golden Retrievers present with hemangiosarcoma in the spleen, liver, or heart.
• Labrador Retrievers: Labradors are susceptible to hemangiosarcoma, especially older dogs. Common sites include the spleen and liver.
• Boxers: Boxers are predisposed to various cancers, including hemangiosarcoma, affecting the heart and skin.
• Schnauzers: Standard and Giant Schnauzers have a higher risk of developing hemangiosarcoma in the spleen and liver.

What does hemangiosarcoma in dogs look like?

Hemangiosarcoma in dogs looks like a mass on internal organs such as the spleen or liver or as dark, bruise-like lesions on the skin in cases of cutaneous hemangiosarcoma.

What are the causes of hemangiosarcoma in dogs?

The causes of hemangiosarcoma in dogs are listed below.

• Genetic Predisposition: Certain breeds have a higher genetic risk, implying that inherited traits contribute to cancer.
• Environmental Factors: Exposure to certain chemicals and toxins, such as pesticides or industrial pollutants, increases the risk of hemangiosarcoma.
• Sun Exposure: Prolonged exposure to ultraviolet (UV) light is what causes hemangiosarcoma in dogs with light-colored or thin coats.
• Age: Older dogs are more commonly affected by hemangiosarcoma, suggesting age-related changes in cellular repair mechanisms.
• Immune System Dysfunction: Compromised immune function makes it harder for the body to detect and destroy cancerous cells, contributing to hemangiosarcoma.

Are older dogs more susceptible to hemangiosarcoma?

Yes, older dogs are more susceptible to hemangiosarcoma. Dogs above 10 are at significant risk of the disease. “The mean age of dogs diagnosed with hemangiosarcoma was 10 years, and most tumors were in the spleen,” according to the study by Brown, N. et al. titled “Canine hemangiosarcoma: retrospective analysis of 104 cases,” 1985.

Aging results in reduced immune function, making older dogs less equipped to combat and eliminate cancerous cells. Studies indicate that certain breeds, such as Golden Retrievers and German Shepherds, have a higher predisposition to developing hemangiosarcoma as they age.

Does Hemangiosarcoma Affect a Dog's Heart?

Yes, hemangiosarcoma affects the dog’s heart, leading to cardiac tumors. The tumors cause symptoms like lethargy, difficulty breathing, and fluid accumulation in the chest. 

Hemangiosarcoma develops in the right atrium, leading to severe complications such as heart failure and arrhythmias. Cardiac tumors disrupt the normal functioning of the heart, creating irregular heart rhythms and dog heart disease. 

Severe cases of hemangiosarcoma in the heart result in sudden collapse or death of the affected dog. 

What are the symptoms of hemangiosarcoma in dogs?

The symptoms of hemangiosarcoma in dogs are listed below.

• Lethargy: A general lack of energy and reluctance to engage in usual activities.
• Weakness: Reduced strength and stamina, often noticeable during exercise or play.
• Pale Gums: The gums appear pale or white due to anemia caused by internal bleeding.
• Abdominal Distension: Swelling of the abdomen due to fluid accumulation or tumor growth, common in cases involving the spleen or liver.
• Sudden Collapse: Collapse occurs due to sudden and severe internal bleeding, especially with splenic hemangiosarcoma.
• Difficulty Breathing: Labored breathing is visible in cases where tumors affect the lungs or heart, causing respiratory distress.

When do symptoms of hemangiosarcoma typically occur in dogs?

Symptoms of hemangiosarcoma in dogs typically occur when the tumor is advanced or has reached a critical stage. The condition is largely asymptomatic in the early stages. “Hemangiosarcoma in dogs often lacks apparent symptoms in early stages, but becomes apparent due to hemorrhagic events following the rupture of malignant vascular cell structures,” according to the study by Tinsley, A. titled “Canine Hemangiosarcoma: A Certainly Less Than Ideal, Very Ugly Cancer,” 2020. Dogs show no symptoms until internal bleeding or organ dysfunction, making early detection challenging.

What are the risk factors for hemangiosarcoma in dogs?

The risk factors for hemangiosarcoma in dogs are listed below.

• Breed Predisposition: German Shepherds, Golden Retrievers, Labrador Retrievers, Boxers, and Schnauzers, have a higher genetic predisposition to hemangiosarcoma.
• Age: Older dogs are more commonly affected, indicating age-related changes in cellular processes that contribute to hemangiosarcoma.
• Gender: Male dogs are slightly more prone to hemangiosarcoma than females.
• Genetics: Familial history of the disease within specific breeds increases the risk of occurrence.
• Environmental Factors: Exposure to certain chemicals, toxins, or environmental pollutants leads to hemangiosarcoma in susceptible dogs.

What are the complications of hemangiosarcoma in dogs?

The complications of hemangiosarcoma in dogs are listed below.

• Internal Bleeding: Sudden and severe internal bleeding occurs, leading to life-threatening situations due to the fragile nature of blood vessel tumors.
• Organ Dysfunction: Tumors impair the function of affected organs such as the spleen, liver, or heart, causing symptoms like abdominal distension, jaundice, or heart failure.
• Metastasis: Hemangiosarcoma is able to spread (metastasize) to other organs, complicating treatment and prognosis.
• Thromboembolism: Tumor fragments or blood clots travel through the bloodstream and block blood vessels in distant organs, causing further complications.
• Pain and Discomfort: Tumors cause pain and discomfort for the affected dog as they grow and invade surrounding tissues.

How do veterinarians diagnose hemangiosarcoma in dogs?

Veterinarians diagnose hemangiosarcoma in dogs through diagnostic tests such as ultrasound, x-rays, and biopsy of the suspected tumor. 

Ultrasound is the first step in diagnosing hemangiosarcoma, allowing veterinarians to visualize the internal organs for signs of tumors or abnormal growths. X-rays evaluate the extent of the disease's spread, especially in the lungs and bones. 

A biopsy of the suspected tumor confirms the presence of cancerous cells and determines the specific type of cancer present.

Where can you seek a diagnosis for hemangiosarcoma in dogs?

You can seek a diagnosis for hemangiosarcoma in dogs at specialized veterinary clinics. Specialized facilities have advanced imaging technologies such as ultrasound, MRI, and CT scans to aid in the diagnostic process. 

The multidisciplinary approach to diagnosing hemangiosarcoma involves veterinary oncologists, internal medicine specialists, and radiologists.

Renowned institutions offering specialized care for hemangiosarcoma include the Cornell University College of Veterinary Medicine and the University of California, Davis School of Veterinary Medicine. 

How is hemangiosarcoma diagnosed in dogs?

Hemangiosarcoma is diagnosed in dogs through ultrasound, CT scan, MRI, bloodwork, and echocardiogram to assess the presence and extent of tumors.

An ultrasound diagnoses hemangiosarcoma by imaging the abdomen and thorax, while CT scans provide detailed cross-sectional images to map the location and spread of cancer cells. 

MRI offers visuals of tumors and aids in accurate diagnosis and treatment decisions. Bloodwork evaluates blood cell counts, organ function, and markers for hemangiosarcoma. 

Echocardiograms assess heart function and detect metastases in the heart, aiding in prognosis and treatment planning.

What is the typical prognosis for a dog diagnosed with hemangiosarcoma?

The typical prognosis for dogs diagnosed with hemangiosarcoma is generally poor. Survival statistics for hemangiosarcoma show a median survival time of 1-2 months without treatment. Only a small percentage of dogs survive beyond 1 year. 

Factors that influence the prognosis of hemangiosarcoma in dogs include the location and size of the tumor and the presence of metastasis. Tumors located in the heart or major blood vessels pose greater challenges for treatment and overall survival. Larger tumors are associated with a poorer prognosis.

How long can a dog survive with hemangiosarcoma?

A dog can survive with hemangiosarcoma for 2-3 months. The expected survival rate after treatment in some dogs is up to one year. “The median survival time for dogs with splenic hemangiosarcoma treated by splenectomy alone is 86 days, with a one-year survival rate of 6.25%,” according to the study by Wood, C. et al. titled “Prognosis for dogs with stage I or II splenic hemangiosarcoma treated by splenectomy alone: 32 cases (1991-1993),” 1998.

Early detection and intervention help catch potential issues early on. Palliative care improves the quality of life for diagnosed dogs by focusing on symptom relief and pain management.

What are the treatment options for hemangiosarcoma in dogs?

The treatment options for hemangiosarcoma in dogs are listed below.

• Surgery: Surgical removal of the tumor is recommended for localized tumors in the spleen, liver, or skin. Complete removal is challenging due to the aggressive nature of the cancer and its spreading tendency.
• Chemotherapy: Chemotherapy targets remaining cancer cells after surgery or to manage the disease in cases where surgery is not feasible. 
• Radiation Therapy: Radiation therapy shrinks tumors or alleviates symptoms in cases where surgery is not an option or to treat tumors that are partially removed.
• Palliative Care: Palliative care involves pain management, dietary support, and other supportive therapies to manage symptoms and enhance comfort in advanced cases.
• Clinical Trials: Participation in clinical trials offers access to new treatment options or experimental therapies that improve outcomes for dogs with hemangiosarcoma.

How effective is surgery in treating hemangiosarcoma?

Surgery is effective in treating hemangiosarcoma by removing the primary tumor and extending survival time. Surgery is followed by chemotherapy to address metastasis. “Surgery is a treatment option for hemangiosarcoma, but survival times are usually short (usually 1 year), except for patients with superficial dermal hemangiosarcoma (HSAs),” according to the study by Smith, A. titled “Hemangiosarcoma in dogs and cats,” 2003.

Surgery cures localized tumors, alleviates symptoms, and improves quality of life. Postoperative chemotherapy is advisable to target any remaining cancer cells and reduce the risk of relapse. 

Are there chemotherapy options for dogs with hemangiosarcoma?

Yes, there are chemotherapy options for dogs with hemangiosarcoma. Drugs such as doxorubicin help manage the disease and prolong survival alongside surgery. “Chemotherapy with doxorubicin and cyclophosphamide improves survival with acceptable morbidity in patients with early-stage hemangiosarcoma,” according to the study by Sorenmo, K. et al. titled “Chemotherapy of canine hemangiosarcoma with doxorubicin and cyclophosphamide,” 1993.

Other chemotherapy drugs used for hemangiosarcoma in dogs are vincristine, cyclophosphamide, and prednisone, each targeting different aspects of the disease. Ongoing research in veterinary oncology is exploring new drug combinations and treatment protocols to enhance effectiveness while minimizing adverse reactions. 

Can CBD oil help manage symptoms in dogs with hemangiosarcoma?

Yes, CBD oil helps manage symptoms in dogs with hemangiosarcoma, providing pain relief and improving quality of life. “In a pilot study using CBD and THC, advanced cancer patients showed overall symptom benefit,” according to the study by Soe, M. et al. titled “Efficacy and Mechanisms of Cannabis Oil for Alleviating Side Effects of Breast Cancer Chemotherapy (CBC2): Protocol for Randomized Controlled Trial,” 2023.

CBD oil has anti-inflammatory and anti-oxidative properties, which are beneficial in reducing pain and inflammation in dogs. Some pet owners report anecdotal evidence of their dogs experiencing improved mobility and appetite when using it. CBD oil shows promise, but it is not a cure-all, and there are limitations to its efficacy. 

Are there any known preventative measures for hemangiosarcoma in dogs?

Yes, there are known preventative measures for hemangiosarcoma in dogs. Regular veterinary check-ups and early screening for high-risk breeds help detect and manage the disease's progress. “Start cancer screening for dogs at the age of 7, or as early as age 4 for breeds with lower median age at cancer diagnosis, to increase the likelihood of early detection and treatment,” according to the study by Rafalko, J. et al. titled “Age at cancer diagnosis by breed, weight, sex, and cancer type in a cohort of more than 3,000 dogs: Determining the optimal age to initiate cancer screening in canine patients,” 2023.

Hemangiosarcoma’s asymptomatic nature in the early stages makes it difficult to diagnose until it has reached an advanced state. The aggressive nature of the cancer means that by the time symptoms manifest, the disease has progressed significantly.