Due to the active development of decorative and service dog breeding and the growth of the dog population in the urban environment, non-infectious animal pathologies are becoming a serious problem.
It is for this reason that scientists today recognize that abdominal diseases pose a serious threat to the health of pets (previously, the key attention of veterinarians was focused on the treatment of diseases of the musculoskeletal system in dogs).
Moreover, even with timely treatment, it is very difficult to predict how long a dog will live, or whether it will survive at all. Therefore, if a dog has a severely enlarged spleen, it is very important to take it to a veterinary hospital as soon as possible.
Functions and principles of operation of the body
The spleen is a single organ, quite large, located in the upper left part of the abdominal cavity (the stomach is at the back). Visually it resembles a gland and a large tongue. The spleen consists of two parts - red and white pulp (pulp), each of which performs specific tasks. The red pulp (about 80%) is responsible for filtering the blood, utilizing protein and iron.
White pulp (20% of the total volume) recognizes pathogenic microorganisms, neutralizes them, protects the immune system from subsequent infections, and replenishes the reserves of immune system cells and lymphocytes.
In general, the tasks of the spleen include participation in the metabolism of iron and protein, immune, filtration and hematopoietic functions.
Thus, while not being a vital organ, the spleen nevertheless performs a number of functions aimed at the normal functioning of the body in general and the immune system in particular.
Causes of hemangioma
The reasons for the formation of hemangiomas in animals are not fully understood. The development is based on the proliferation of endothelial cells with the formation of capillaries.
Causes of hemangiomas:
- genetic, breed predisposition;
- traumatic injuries to the skin, blood vessels, mucous membranes;
- age-related changes in the body;
- viral and bacterial infections;
- cardiovascular pathologies;
- disruption of intrauterine development during the formation of the vascular system;
- hormonal imbalances.
The appearance of hemangiomas is promoted by malignant tumors, systemic, chronic diseases of internal organs, for example, liver pathologies (cirrhosis). In puppies, hemangiomas can be caused by the fact that the bitch suffered from some kind of infection during the period of gestation.
Types of tumors that form in the spleen
An enlarged spleen can be triggered by various factors: infectious diseases and inflammatory processes, congestion caused by liver pathologies, cardiovascular failure, hematomas.
The changes are temporary and after appropriate treatment the indicators return to normal. It is much worse if neoplasia, splenomegaly and other neoplasms of the spleen in dogs contribute to the increase.
Tumors can be of two types - malignant and benign. The most dangerous and aggressive malignant neoplasm is hemangiosarcoma, which interferes with blood clotting, provokes bleeding and metastasizes.
Often diagnosed splenomegaly, which is a uniform enlargement of the spleen, is not cancer.
In some cases, cancer of the lymphoid tissue and blood cells is diagnosed, which can spread to the spleen. We are talking about malignant neoplasms such as lymphoma, lymphosarcoma, and leukemia.
Neoplasms (tumors) of the spleen
Incidence and risk factors
Tumors of the spleen can develop from all tissues that make up the organ; probable sources of tumors can be blood vessels, lymphoid tissues, smooth muscles and connective tissue of the fibrous capsule.
The main reason for searching for a tumor of the spleen is splenomegaly - an increase in the volume of the organ compared to the norm. Splenomegaly is divided into homogeneous (increase in volume while maintaining shape) and nodular (formation of one or more nodes in the parenchyma. Below are the main pathological causes of splenomegaly in dogs and cats.
Table: Pathological causes of splenomegaly in dogs.
Non-neoplastic lesions • Hyperplastic nodes • Hematoma • Splenitis (abscess, granulomas) • Organ congestion (congestive heart failure, splenic torsion, acute dilation/volvulus of the stomach, some drugs) • Infections (fungal, bacterial, viral) Benign tumor lesions • Hemangioma • Lipoma • Leiomyoma • Myelolipoma Malignant tumor lesions • Hemangiosarcoma • Lymphoma • Undifferentiated sarcoma • Fibrosarcoma • Leiomyosarcoma • Malignant histiocytosis • Plasmacytoma • Mastocytoma • Liposarcoma • Mesenchymoma • Myxosarcoma • Histiocytic sarcoma • Osteosarcoma • Metastasis ic carcinoma
Table: Pathological causes of splenomegaly in cats.
Non-neoplastic lesions • Congestion • Splenitis • Hypereosinophilic syndrome • Hematoma • Extramedullary hematopoiesis Malignant tumor lesions of cats • Mastocytoma • Lymphoma • Myeloproliferative diseases • Hemangiosarcoma.
In dogs, when the spleen is enlarged, the law (rule) of two thirds applies: two thirds of cases of splenomegaly in dogs develop due to neoplasia, and two thirds of these tumors are hemangiosarcoma. In cats, the main cause of splenomegaly (up to 75%) is malignancy, and most often it is mastocytoma (first most common) or lymphoma (second most common).
Neoplasms of the spleen are more often observed in middle-aged and elderly dogs, with a breed predisposition in medium and large breeds. The German Shepherd is not in first place in terms of predisposition to the formation of hyperplastic nodes, hematomas, hemangiosarcoma and lymphosarcoma, followed by the Golden Retriever and Labrador.
Splenic hemangiosarcoma most often affects dogs aged 8 to 13 years. A breed predisposition to the development of tumors has been noted in the German Shepherd and Golden Retriever.
With nodular hyperplasia of the spleen, German shepherds, cocker spaniels, Labradors, golden retrievers and poodles are predisposed to the disease. There is a possible predisposition to nodular hyperplasia in females.
Biology, behavior, predictions
Below is a description of the most common spleen tumors.
Hemangiosarcoma of the spleen.
Splenic hemangiosarcoma develops from transformed endothelium of blood vessels and is characterized by aggressive behavior - local invasive growth and high metastatic potential. More than half of dogs already have macroscopically detectable metastases at the time of diagnosis. The typical localization of tumor metastases is the liver and lungs; metastases form less frequently in other organs (omentum, peritoneum, brain, muscles and bones). The average lifespan of dogs with surgical treatment alone ranges from 3 weeks to 2 months; with postoperative treatment with chemotherapy drugs, the lifespan can increase to 6 months. Feline hemangiosarcoma is characterized by less aggressive behavior and is much less common than in dogs.
Nodular (nodular) hyperplasia of the spleen in dogs.
Canine nodular splenic hyperplasia is a neoplastic regional proliferation of normal splenic parenchyma cells. Nodular hyperplasia, depending on the ratio of cell components, can be divided into lymphoid, hematopoietic, plasmacytic, fibrohistiocytic and mixed.
Nodular fibrohistiocytic hyperplasia of the spleen is accompanied by proliferation in the organ of a mixed population of spindle cells mixed with hematopoietic cells, plasma cells and lymphocytes. Nodular fibrohistiocytic hyperplasia of the spleen can be a transitional form between a node and a malignant tumor (eg malignant fibrous histiocytoma or generalized histiocytic sarcoma).
The treatment of choice for fibrohistiocytic nodular hyperplasia of the spleen is splenectomy; the average survival time after surgery is about 12 months. Survival is largely determined by a low lymphoid-fibrohistiocytic ratio and a high mitotic index; these factors are associated with a decrease in average life expectancy.
Mastocytoma of the spleen.
Splenic mastocytoma is more common in cats, in which up to 50% of mastocytosis affects the visceral organs. Splenic mastocytosis accounts for approximately 50% of the causes of splenic hyperplasia in cats. The average age of tumor onset in cats is 10 years; no breed or gender predisposition has been identified. A malignant course with widespread dissemination and the formation of distant metastases is characteristic. Paraneoplastic syndrome in mastocytoma of the spleen of cats can be caused by the release of histamine by tumor cells (gastric ulcers, vomiting, anorexia). Splenectomy gives an average survival for feline splenic mastocytoma of about 12 months; the role of chemotherapy is uncertain.
In dogs, mastocytoma primarily of the spleen is quite rare; the visceral form of mastocytosis is more often noted, which follows primary skin lesions.
Lymphoma of the spleen.
Lymphosarcoma of the spleen in most cases presents as part of a systemic disease; in rare cases, lymphoma in dogs may be limited to the spleen.
Malignant histiocytosis of the spleen
Causes of spleen tumors
The exact reasons contributing to such a phenomenon as an enlarged spleen in dogs have not yet been established.
Benign neoplasms are most often the result of intense activity of the spleen or insufficient blood supply to the organ. The danger of non-cancerous tumors is that over time they can turn into cancer.
This can occur due to rapid cell division and mutation. However, this does not always happen; very often the degeneration of hyperplasia does not occur. It all depends on external and genetic factors.
Malignant neoplasms can be the result of genetic abnormalities caused by exposure of the body to radiation, chemicals, and hormones. Cells of an organ that have undergone mutation complicate the normal process of cell death and regeneration.
This occurs due to the activation of cancer genes, the inactivity of suppressor genes, and changes in genes responsible for apoptosis (the regulated process of programmed cell death).
As for cancers of the blood and lymphatic tissues, they are caused by various viral infections.
If we talk about the frequency of tumors, they are quite common in dogs. It is believed that some breeds, mainly short-haired (pit bull terriers, Labradors, boxers and others), have a predisposition to the development of neoplasms.
It is noteworthy that hemangiosarcoma is often diagnosed in German Shepherds, and malignant histiocytosis in Bernese Mountain Dogs.
Age is of great importance, this applies to individuals of both sexes. In older animals (after 5 years), tumors develop much more often than in young dogs. However, there are cases where neoplasms were diagnosed even in puppies at the age of 4-5 months.
Causes and pathogenesis in dogs:
Sarcoma in dogs develops from actively dividing, immature tissue. It is present in all organs and systems of the animal. A tumor can develop from bone or cartilage cells, adipose or lymphoid tissue, or epidermis. It is not associated with a specific organ, but is characterized by an aggressive course and early metastasis. Veterinarians cannot answer why sarcoma occurs in dogs. But there are a number of factors that provoke the development of the tumor process. The onset of the disease is facilitated by:
- viral infections – papillomatosis, herpes;
- exposure to adverse environmental conditions;
- promiscuity with homeless animals – transmissible sarcoma in dogs;
- intoxication with carcinogenic substances;
- mutation processes;
- hormonal imbalances - for example, sarcoma of the uterus in a dog.
Symptoms and clinical course
At home, it is not difficult to determine an enlarged spleen in dogs. It puts pressure on other abdominal organs, so the stomach increases in size and becomes bloated.
Characteristic features also include:
- nausea, vomiting, loss of appetite (due to pressure on the stomach);
- temperature increase;
- the appearance of small blood spots on the skin and gums (petechial hemorrhages);
- weight deficiency;
- weakness, decreased activity;
- anemia;
- diarrhea;
- renal failure (in severe cases).
If the cause of the enlarged spleen is a malignant neoplasm, a symmetrical enlargement of the lymph nodes is noted. When the level of calcium and gamma globulin increases, which is typical for cancer, the dog is constantly thirsty, therefore, urination becomes more frequent.
A rapidly growing tumor can cause rupture of the spleen, acute collapse, severe bleeding in the peritoneum, and breathing problems, which poses a direct threat to the dog’s life.
Defeating cancer, the symptoms and treatment of which are interconnected, is possible only after a high-quality diagnosis.
Treatment of sarcoma in dogs:
After making a diagnosis of “sarcoma in dogs,” the doctor will develop tactics for managing the animal, taking into account its age, stage and type of disease, and the presence of secondary tumors. The treatment is complex. Removing sarcoma from a dog is not a method that guarantees recovery and absence of relapses. Chemotherapy and radiation therapy are indicated. The use of aggressive drugs reduces the risk of secondary tumors.
Treatment of bone sarcoma is carried out using platinum drugs. This increases the pet's lifespan. Without chemotherapy after surgery, the average life expectancy of an animal is 3 months. Radiation therapy relieves pain, but is indicated in cases where the integrity of the bone is not compromised. Canine transmissible venereal sarcoma requires the formation of a urethra in the abdominal wall. Conservative therapy for this form of the disease is used for inoperable carcinomas.
If the disease has spread to other organs and there is active metastasis, then in this case symptomatic and palliative therapy is indicated. If treatment is ineffective, the doctor will recommend euthanizing the pet. Oncological diseases are not the prerogative of humans. Animals also suffer from them. The owner’s task is to monitor the animal’s health and eliminate provoking factors. And if suspicious symptoms appear, examine your pet and follow all doctor’s orders.
Diagnosis of spleen cancer
The diagnosis of cancer is preceded by certain diagnostic measures. A visual examination of the animal and the clinical picture are, of course, not enough.
The difficulty is that neither ultrasound nor x-ray can differentiate cancer from a benign tumor (hyperplasia) with 100% accuracy. A blood test may also not be entirely informative, since the anemia detected in blood samples is nonspecific. Cancer cells in them can be detected only in certain types of tumors.
Since splenic cancer in a dog has all sorts of clinical manifestations, and the spleen is in close relationship with other abdominal organs, it is for this reason that diagnosis should be carried out in a complex and include clinical, hematological and sonographic studies, angiocontrast radiography and the Doppler effect.
To identify a tumor, you will need a sample of it, which is obtained during a diagnostic operation and subsequent microscopic examination of specially prepared and stained tissue sections - histopathology.
This procedure makes it possible to obtain information about the tumor, which helps predict the further development of cancer. A research method such as cytology, which is the study of cell samples, is not informative for spleen tumors.
Neoplasms of lymphoid tissue can degenerate into cancerous tumors, so their diagnosis is extremely difficult.
Treatment of spleen tumor
When faced with the problem of an enlarged spleen in a dog, especially when it comes to cancerous tumors, the owner must understand that the treatment will be complex and long-term, requiring a lot of strength and endurance.
For malignant and benign formations, treatment is carried out surgically, involving removal of the organ. The operation is called splenectomy. In hyperplasia, the tumor affects only the spleen; in cancer, it extends beyond its boundaries and metastasizes. But surgery does not guarantee a complete recovery; it only slows down the progress of tumor development.
Chemotherapy is one of the most effective ways to induce remission, thereby prolonging the life of a dog if it develops cancer of the blood, mast cells, or lymphatic system.
However, the poisons and toxins that are part of the drugs used in chemotherapy, at the same time, have a detrimental effect on other organs, especially the liver. Kidney failure can develop in dogs, symptoms and treatment are described here. Unfortunately, the optimal chemotherapy treatment regimen for splenic tumors in dogs has not yet been developed.
Cancer treatment can be done with steroid drugs, which are anti-inflammatory drugs based on hormones produced by the adrenal glands. However, such therapy provides only a short-term effect (several months) and can provoke resistance of the malignant neoplasm to other drugs used in chemotherapy.
At a certain stage of treatment, the cancerous tumor may stop growing, but not disappear. To prevent tissue death and subsequent intoxication of the body, the spleen should be removed.
During the postoperative period, you need to ensure that the dog does not lick the stitches - this contributes to their separation and infection. The incision site must be clean and dry. If discrepancy cannot be avoided, swelling or bleeding occurs, you should immediately inform your veterinarian.
After the operation, the doctor issues a histopathological report, in which he gives a preliminary prognosis of the further development of the tumor.
No doctor can talk about final recovery from cancer. Competent and timely treatment guarantees the cessation of tumor growth and the absence of metastases, but no more. Under unfavorable factors, a new outbreak of the disease can be expected. The prognosis largely depends on the type of neoplasm.
Dogs with grade 1 and 2 benign tumors survive at least 12 months after splenectomy. While with stage 3 cancer, even if the affected organ is removed and subsequent chemotherapy, only 5% of dogs survive.
What happens in a dog's body after the spleen is removed? Most likely, there is an increase in glycogen in the liver, which contributes to the accumulation of fat cells in this organ.
Enlarged spleen, its causes and treatment
The spleen is an organ about which the average person knows very little and therefore, if problems arise with it, they do not know what to do about it and why this happens.
The spleen performs the role of a blood filter and immune function in the body, mainly. It is bean-shaped, located in a capsule and measures 11 cm in length, 6-9 cm in width, weighs 150-200 g in an adult, and is located in the abdominal cavity, in the left hypochondrium. The spleen itself cannot hurt, just like the liver, but as its size increases, a feeling of discomfort or pain arises due to pressure on neighboring organs. The spleen is the largest lymph node in the human body. It cleanses the blood of infections, antibodies, as well as old red blood cells, regulates the number of platelets and is involved in metabolism.
Disease of the spleen in dogs. Enlarged spleen in animals: how to treat
The spleen is a large formation that performs a large number of functions. If they are violated, various changes in this organ are possible, including an increase in its size.
The development of splenomegaly in animals is a fairly common pathology associated with a large number of etiological factors. It is quite difficult to make such a diagnosis without special research, but its presence can be suspected by changes in the pet’s behavior.
This is due to the fact that an enlarged spleen in dogs and cats causes certain unpleasant symptoms.
Spleen diseases in dogs
The spleen is a fairly sensitive organ that responds to many adverse effects. This is why an enlarged spleen in dogs is a very common occurrence.
However, it is very important to figure out in time what exactly provokes splenomegaly.
According to statistics, the largest number of diagnosed cases of this pathology are associated with the development of tumors in the tissues of this organ.
Oncological, based on the principle of occurrence, animal diseases are classified into primary and secondary (another name is multicentric). Primary splenic tumors in dogs are usually divided into hemangiomas, hemangiosarcomas, and various types of sarcomas.
Hemangiosarcomas are the most common. This type of oncology is characterized by a fairly high risk of metastasis, which occurs in the early stages of the disease.
If this malignant neoplasm ruptures, there is a high probability of severe bleeding into the abdominal cavity.
Often this development of events occurs in dogs aged eight to nine years.
Functions and principles of operation of the body
In normal condition, the spleen performs a large number of vital functions:
- hemorrhage;
- depositing volumes of blood that replenish the bloodstream in case of emergency;
- filtering of dead blood cells, toxic substances, and bacteria;
- fulfillment of the protective properties of the immune function.
At the same time, surgical removal of the spleen is not a catastrophic injury. Moreover, over time, the animal’s body adapts to changes and functions almost fully.
Enlarged spleen: causes
One should take into account the fact that an enlarged spleen in animals can be caused not only by the development of tumors.
An important factor in this process is thrombosis of the vessels of this organ and the development of ischemic heart attack, various congestion.
Splenomegaly is also possible due to injuries and hematomas, exposure to infections and toxic substances, as well as torsion of the splenic pedicle. Sometimes an enlarged spleen can be caused by the presence of advanced helminthiasis.
Treatment of an enlarged spleen
Treatment for an extremely enlarged spleen directly depends on the factor that caused such changes. If splenomegaly is caused by the development of an oncological process, surgical intervention is necessary. However, in case of a malignant tumor, surgical treatment is not able to save the animal and can only slow down the course of the disease.
In order to prevent relapses or at least reduce the likelihood of their occurrence, chemotherapy treatment is prescribed after splenectomy.
For this purpose, either one drug or a combined effect on the oncological process can be used.
It should be taken into account that the prognosis in the presence of a malignant process in a dog’s body is unfavorable.
In the same case, if the enlargement of the spleen is associated with severe intoxication, detoxification therapy and restorative drugs are prescribed. If there are infectious processes in the body, antibiotics are prescribed (most often broad-spectrum).
Enlarged spleen in cats
As for felines, they are more susceptible to splenomegaly than dogs. This pathology is very common not only in older animals, but also in kittens.
Moreover, symptoms of spleen enlargement in cats are more pronounced. The key symptom of this pathology is a noticeable enlargement of the lymph nodes.
In addition, with pressure from the organ on the gastrointestinal tract, complete anorexia and vomiting may occur. Disorders of bowel movements, weight loss and constant bloating may occur.
Due to the relationship of the spleen with the process of blood formation, changes in the balance of formed elements are possible (lymphocytosis predominates with a shift towards abnormal cells).
Reasons for the development of the disease
The etiological factors of splenomegaly in cats are practically no different from the causes of this pathology in dogs. However, it should be taken into account that the development of the pathological process may be affected by differences in the diet of animals (in particular, the consumption of raw fish, which can lead to helminth infestation).
