犬の心臓腫瘍を見分ける：種類、症状とケアのポイント

執筆者 TCMVET | 11月 1, 2024 | 犬の癌と腫瘍

Heart tumors in dogs, while uncommon, are conditions pet owners should be aware of, especially as dogs age. These tumors, which form in or around the heart, can vary in type and severity. Knowing about the different tumor types and their potential impacts can help pet owners seek timely veterinary support and manage their dog’s health effectively.

Common Types of Heart Tumors in Dogs

Heart tumors can be classified into primary tumors, which develop in the heart itself, and secondary tumors, which spread to the heart from other parts of the body.

1. Primary Heart Tumors
   Primary heart tumors originate directly within the heart’s structures, often in the heart muscle, blood vessels, or fibrous tissues.
   • 血管肉腫
     This is a fast-growing malignant tumor originating from the blood vessels in the heart. It is aggressive and has a high potential for metastasis, often requiring urgent intervention.
   • Fibromas and Fibrosarcomas
     Tumors that develop from fibrous tissue, such as that found in the heart valves, are termed fibromas if they are benign and fibrosarcomas if malignant. Fibrosarcomas are more invasive, potentially spreading to surrounding organs.
   • Myxomas and Myxosarcomas
     Myxomas are benign tumors found in the heart’s upper chambers (atria). When malignant, they are termed myxosarcomas and have a higher likelihood of spreading, affecting the dog’s overall heart function.
   • Rhabdomyosarcomas
     A rarer form of tumor originating in the skeletal muscle tissue of the heart, rhabdomyosarcomas are always malignant and can cause significant cardiac complications.
2. Secondary Heart Tumors
   Secondary heart tumors reach the heart through metastasis from other areas. These include:
   • リンパ腫
     A type of malignant tumor arising from lymph nodes, lymphomas may eventually impact the heart, complicating cardiac health.
   • Neurofibromas
     Benign tumors stemming from nerve fibers, neurofibromas can affect heart tissue without spreading, though they can still disrupt heart function depending on their location.
   • Granular Cell Tumors
     These tumors can be benign or malignant and often affect the heart secondarily. Their origins are unclear, making their behavior in the body unpredictable.
   • 骨肉腫
     Malignant bone tumors like osteosarcomas can metastasize to the heart, posing serious health risks due to their aggressive spread.

症状の認識

Heart tumors in dogs can be tricky to detect due to their internal nature and sometimes mild symptoms in the early stages. Common signs include lethargy, breathing difficulties, fainting, and an irregular heartbeat. As these symptoms overlap with other conditions, veterinary evaluation is necessary for accurate diagnosis.

Diagnosis and Care Tips

Diagnosis often involves advanced imaging techniques such as ultrasound, MRI, or CT scans to assess the heart’s condition. Blood tests and tissue biopsies may also be required to confirm the tumor type.

Caring for a dog with a heart tumor involves regular monitoring and supportive care, especially in cases where treatment options like surgery, radiation, or chemotherapy are not feasible. Dietary support, light exercise, and a calm environment can help improve a dog’s quality of life.

The outlook for dogs with heart tumors depends on factors like tumor type, location, and overall health. While some benign tumors can be managed without intervention, malignant tumors often have a guarded prognosis. Nevertheless, early detection and supportive care can extend a dog’s comfort and longevity.