Spleen Cancer (Hemangiosarcoma)
Splenic hemangiosarcoma is aggressive and can present as sudden collapse from internal bleeding.
What is Spleen Cancer (Hemangiosarcoma)?
The classic scenario is a large-breed senior dog who suddenly collapses at home, becomes pale, and rallies briefly — from a splenic mass that has ruptured and bled into the abdomen. Roughly two-thirds of splenic masses in dogs turn out to be malignant, and the majority of those are hemangiosarcoma.
Common signs and symptoms
Signs vary between dogs and can be subtle at first. Watch for the following, especially if several appear together or persist for more than a few days:
- Sudden weakness or collapse
- Pale gums
- Abdominal distension
- Panting and restlessness
- Episodes that seem to resolve on their own within hours
Risk factors
Certain dogs are more predisposed. Understanding risk helps you screen earlier and act sooner.
- German Shepherd, Golden Retriever, Labrador Retriever
- Large-breed senior dogs (typically 8+)
When to see a vet
Use this as general triage guidance, not a substitute for veterinary advice.
- Book a routine appointment if: if abdominal ultrasound as part of a senior wellness screen finds a splenic mass, it should be worked up promptly.
- Seek urgent care if: collapse with pale gums is an emergency — go directly to a 24-hour hospital.
Diagnosis and management
Emergency splenectomy stabilises bleeding and provides definitive diagnosis. Chemotherapy after surgery meaningfully extends survival for confirmed hemangiosarcoma. Because the disease is often systemic at diagnosis, honest conversations about goals of care are important.