The spleen is an oblong organ (some would say it is tongue-shaped) seated just below the stomach. Its consistency is similar to that of the liver. While one can live perfectly well without a spleen, the spleen does provide some helpful services to the body.
(original graphic by marvistavet.com)
WHY MIGHT THE SPLEEN NEED TO BE REMOVED?
There are several reasons why the spleen might need to come out. In dogs, by far the main reason is a growth or mass on the spleen which has broken open and started bleeding and much of the discussion below regards this scenario. Other reasons to remove the spleen involve curtailing the pitting function reviewed above. In immune-mediated anemia, the spleen is removing too many red blood cells and the patient is suffering for it. Usually medication is used to suppress the immune-system but sometimes this is inadequate and the spleen must come out. Similarly, animals being considered as blood donors sometimes have their spleens removed to curtail the pitting function and facilitate the detection of blood parasites that might preclude use as a blood donor.
Additional reasons to remove the spleen include infiltration by cancer. In particular, there is a form of mast cell cancer in cats which is largely limited to the spleen and removing the spleen can be provide a long remission or even cure. Sometimes the spleen is ruptured in a trauma and must be removed to control the bleeding. For the most part, spleens are removed because they have grown a mass which has started to bleed so our discussion will begin here.
SPLENIC MASSES – WHY ARE THEY BAD?
Most spleens are removed because they have grown a tumor. Tumors can be benign (like the red pulp hemangioma) or malignant (like the red pulp hemangiosarcoma, white pulp mast cell tumors, or white pulp lymphosarcoma). In dogs, most splenic masses are either hemangiomas or hemangiosarcomas while in the cat they are usually either mast cell tumors or lymphosarcomas.
HEMANGIOMA AND HEMANGIOSARCOMA: THE MOST COMMON CANINE SPLENIC TUMORS
Both these tumors arise from the blood vessels of the red pulp and amount to a bunch of wildly proliferating abnormal blood vessels. Eventually the growth ruptures and the spleen bleeds. When a vascular organ like the spleen bleeds, a life-threatening blood loss can result.
Unfortunately, the splenic mass is certain to bleed again and if the spleen is not removed, eventually the patient will bleed to death.
If the splenic tumor is benign, removing the spleen is curative provided that the patient has not lost too much blood to survive the surgery. Ideally, the splenic mass is detected before it has ever bled and the spleen is removed at a time when the mass is not actively bleeding. Of course, if the splenic mass IS actively bleeding and cannot be stopped with pressure wraps, removing the spleen becomes an emergency surgery; it is not appropriate to try to wait until the bleeding has stopped. Expect blood transfusions to be necessary before, during, and possibly after surgery.
If the splenic tumor is a malignant hemangiosarcoma, the spleen can still be removed to control the bleeding but the problem is that hemangiosarcoma is an aggressive cancer. With the removal of the spleen and primary tumor, the patient is probably spared death by bleeding to death only to eventually succumb to cancer. Since the decision to go to surgery often hinges on whether or not the tumor is malignant, some effort should be made to make this determination if delaying the surgery can be safely done. Chest radiographs and abdominal ultrasound are performed to look for evidence of tumor spread.
If there is evidence of tumor spread: this means the tumor is malignant and best control will entail both removal of the spleen and chemotherapy follow up. Many people opt for euthanasia at this point though newer drugs have held promise. Please see the hemangiosarcoma page for more details.
If there is no evidence of tumor spread: it may be possible to effect a permanent cure by removing the spleen though lack of visible tumor spread does not mean the tumor is benign. An actual piece of spleen tissue will be needed to settle the question of malignancy.
HOW DO WE DETECT SPLENIC MASSES?
There are several ways to detect a splenic mass. The first way, is by physical examination. A large firm mass in the area of the spleen may be palpable during a routine physical examination. From there, radiographs are taken of the belly to see if the mass appears to be on the spleen and radiographs of the chest are taken to see if there is evidence of cancer spread there. Based on these findings (plus basic blood work) a decision for or against spleen removal can be made. Unfortunately, many large dogs are simply too well muscled for splenic masses to be detected in this way.
Another method of detecting a splenic tumor comes on the basic blood panel. An unexplained “responsive anemia” is discovered. A responsive anemia is one typical of bleeding (as opposed to an anemia of chronic disease where red blood cells simply are inadequately produced.) An older large breed dog with an unexplained bleed is highly suggestive of a splenic tumor. The next step would be radiographs to see if a mass is apparent followed by chest radiographs for tumor spread as above. These findings on the blood panel are especially suggestive of a splenic mass if there has been a history of sudden weakness or collapse typical of a recent bleed. Splenic tumors tend to bleed intermittently (and usually insignificantly) prior to a large bleed that produced obvious symptoms. These smaller bleeds are generally enough to alter the blood panel. If blood work is suggestive of a splenic mass, radiographs can be taken to confirm the presence of the mass.
It can be difficult to determine from the radiograph if the mass is coming from the liver or from the spleen.
IF YOU CHOOSE NOT TO REMOVE THE SPLEEN
Unfortunately, eventually the dog will have a bleed from which he cannot recover. If you think your dog is having a bleed at home, you can apply an ace bandage around the belly in a snug manner to essentially apply pressure to the bleed. This is surprisingly effective and may stave off the inevitable temporarily or until you can get your dog to an emergency hospital for more definitive support such as a blood transfusion. There is a Chinese herb called Yunnan Baiyo which can assist in blood clotting and may be helpful in minimizing the severity of future bleeds.
Chemotherapy may still be an option even if the spleen and its malignant tumor are left behind. A newer approach to chemotherapy, called "metronomic" chemotherapy, focuses on eliminating the blood supply of the tumor rather than on killing the tumor directly. Lower doses of chemotherapy drugs are used which leads to far less potential for side effects. If this is something you are considering, it will be necessary to consult an oncologist for the most up to date information.
OTHER REASONS TO REMOVE THE SPLEEN
We have already mentioned the splenic mass as well as excessive red blood cell removal by the spleen as reasons for splenectomy. There are some other situations where splenectomy may be needed:
Page last updated: 1/13/2018