Pet Illnesses

Spleen Tumours in Dogs

Tumours of the spleen are a relatively common type of cancer in dogs. Some breeds are more prone e.g. German Shepherds, but any breed can be affected.

As a rough rule, approximatley 50% of splenic tumours are benign (sometiomes even very big ones) and the rest malignant.

The most common type of malignant sp[lenic tumour is a haemangiosarcoma. It has a nasty habit of spreading to adjacent organs and the base of the heart.

Splenic tumours are very dangerous for dogs. They can rupture at any time with no warning, and because the spleen has a major blood supply to it, a dog can bleed to death very quickly. Affected dogs can be happy and active one minute, then suddenly dying in front of their owner’s eyes. Sometimes, the splenic tumour has a small tear, and there is only a small amount of blood loss. In these cases, the dog may suddenly collapse or go into mild shock, but appear to make a quick recovery. A collapsing dog should have its spleen examined ASAP.

Tumour spleen 3Tumour spleen 10Tumour spleen 17









A ruptured splenic tumour is a life threatening emergency requiring rapid diagnosis, surgery and intensive care. If the dog has a nasty splenic haemangiosarcoma that has spread to adjacent organs, it is more humane to opt for euthanasia as the prognosis is hopeless. If there is no evidence of spread, removal of the spleen can be successful and give the dog extra years of life.

However, we sometimes find splenic haemangiosarcoma have spread elsewhere around the body into tiny tumours (“secondaries” or “metasises”) not visible to the naked eye. The large splenic haemangiosarcoma appears to “control” the growth of the smaller “secondaries” – possibly by producing a chemical which inhibits their growth.

When the large splenic haemangiosarcoma is removed, the growth controlling chemical is removed and the secondaries start to rapidly grow. Sometimes, a dog can be brought back to the vet with advanced cancers all through the body within 1-2 weeks of the spleen being removed. Unfortunately, there is no way of predicting which case will follow this route at the time of surgery.

As part of your dog’s annual health check and vaccinations,
ask your vet to palpate the abdomen to see if there is a mass present

Medium to large sized splenic tumours are easily detected, but smaller ones may be missed.

Regular checkups are vital in the early detection of splenic tumours.