Spleen cyst in an adult and a child

Tumor-like formations in the form of cavities separated from the surrounding tissues can form in various organs, including the spleen. A spleen cyst (ICD-10 code D73.4) is considered rare because it does not always manifest itself, and it is not so easy to find it in the spleen covered with the peritoneum. Often a cyst of this localization is detected during an examination of the abdominal cavity for a completely different reason. [1]

Epidemiology

The widespread use of ultrasound and CT of the abdominal organs has led to the fact that spleen cysts have begun to be detected more often, and now they account for 1% of all diagnosed pathologies of this organ, and only 0.07% of diseases in the general population (according to some other data, 0, 5-2%).

Statistically, nonparasitic cysts account for less than one third of all splenic cysts, and the majority (almost two thirds) are pseudocysts secondary to trauma. Only 10% of all nonparasitic spleen cysts are primary (congenital) cysts, which are most common in children and adolescents and rarely manifest clinically. [2]

Causes spleen cysts

Types of spleen cysts differing in origin have different causes of formation and histological features.

Nonparasitic cysts and a parasitic cyst of the spleen (echinococcal) are distinguished. Nonparasitic cysts of the spleen can be epithelial (true) cysts or pseudocysts (false cysts). [3], [4]

Primary epithelial (epidermoid) cysts of the spleen are congenital, most often solitary (solitary) and rather large (with serous fluid inside). Their formation is associated with impaired embryonic (intrauterine) development or genetically determined defects. This spleen cyst in a child or adolescent is the most common. [5], [6]

Most pseudocysts - the walls of which are made of fibrous tissue, but inside are not lined with epithelium - arise from blunt trauma to the abdomen in the spleen area with accumulation of blood (hematoma). A similar cyst in the spleen in an adult is usually filled with blood and dead cells. In a third of cases, its membrane undergoes calcification, and then a calcified or calcified spleen cyst is determined. [7], [8]

A pseudocyst can be the result of infections, splenic infarction (for example, with thrombosis of the splenic artery), and with pancreatitis, such a cystic formation appears not only in the pancreas, but also in the spleen.

In addition to splenic infarction, the cause of a vascular splenic cyst can be peliosis - the presence of small cysts filled with blood on the surface of the spleen.

A parasitic or echinococcal cyst of the spleen is formed as a result of infection with eggs and primary larvae of the parasitic tapeworm Echinococcus granulosus -  echinococcus , which enter the body through the gastrointestinal tract and with the blood stream into the internal organs. The walls of these cysts are also often calcified. [9], [10]

Risk factors

The tendency to form cysts in the spleen in infants is observed with pathologies of pregnancy and prematurity of newborns; in adults - with increased destruction of blood platelets (thrombocytopenia), chronic viral infections, as well as with systemic lupus erythematosus, aplastic anemia, rheumatoid arthritis and other autoimmune diseases.

Risk factors for the development of a splenic infarction, which can cause the formation of a vascular cyst, are associated with thrombi of the artery supplying the spleen with blood, atherosclerosis, systemic connective tissue diseases, and leukemia. And the risk of developing peliosis increases with chronic alcoholism, HIV, tuberculosis, taking anabolic steroids and oral contraceptives. [11]

Pathogenesis

Any of the above causes can negatively affect the liver  and cause tissue damage.

Considering the pathogenesis of cystic formation in the spleen, experts emphasize its importance as one of the organs of the  body's immune system  , as well as multifunctionality, including the deposition of erythrocytes and platelets, the production of leukocytes and antibodies, the metabolism of hemoglobin from spent erythrocytes, phagocytosis and blood filtration (including from products apoptosis and pathological necrosis and toxic substances).

How primary (congenital) cysts form in the spleen, until the researchers finally figured out, but suggested several versions. [12]

The formation of the spleen in the dorsal part of the mesentery from the mesodermal mesenchyme (with the participation of hematopoietic stem and dendritic cells) begins at the beginning of the second month of pregnancy, and until its completion, the spleen is a hematopoietic organ that synthesizes erythrocytes.

The characteristic structure of the organ (lobules, trabeculae, parenchyma, venous system) is formed from the 15th week of gestation, and from about 18-19 weeks the stage of accumulation and differentiation of lymphocytes (T-cells) begins. [13]

So, the formation of cysts can be the result of the introduction of cells of the mesothelial membrane of the peritoneum into the splenic grooves of the fetus (and their metaplasia) or the inclusion of the endoderm of the inner germ layer into the lymphatic space or pulp of a developing organ. 

The mechanism of development of an echinococcal cyst is due to parasitic invasion: entering the spleen tissue in the blood stream, the primary larvae of the tapeworm Echinococcus granulosus are transformed into the next stage - the Finn, which is a shell-covered capsule for the further development of the parasite. Around these capsules a parasitic cyst of the spleen or liver is formed. [14]

Symptoms spleen cysts

When a small spleen cyst is accidentally detected, symptoms are absent in most patients. But with larger sizes, the first signs can manifest themselves in the form of uncomfortable sensations on the left in the hypochondrium and the presence of a painless mass in the upper left abdomen (found in a third of patients on palpation).

In addition, belching, rapid satiety when eating, aching pain in the left side , nausea and sometimes vomiting after eating, flatulence, diarrhea may appear .

Also, on examination, spleen edema and splenomegaly may be noted  , especially if it is a parasitic cyst. Also, with an echinococcal cyst, there is general weakness and the temperature rises slightly.

A congenital spleen cyst in a fetus can be detected during prenatal ultrasound, starting from the 20th week of pregnancy. A larger congenital cyst in the spleen of a newborn can be palpable on palpation and, if enlarged, cause symptoms of vomiting and intestinal upset. Most often it is a solitary or solitary cyst of the spleen in newborns.

Read also:

• Cyst in a newborn
• Cyst in a child: main pitchfork, localization, causes of occurrence, symptoms

Complications and consequences

Why is a spleen cyst dangerous? Usually it does not cause complications, however, the main negative consequences of this education include:

• bleeding into the "bag" of the cyst, fraught with violation of the integrity of its walls;
• rupture of a spleen cyst with hemorrhage and the spread of its contents into the abdominal cavity (with cysts larger than 5 cm, the risk is 25%), as a result of which symptoms of an acute abdomen and the development of peritonitis are possible;
• infection of the cyst with suppuration, leading to intoxication of the body;
• the spread of parasites from the echinococcal cyst to other organs.

Experts do not exclude the possibility of (extremely rare) malignant transformation of the secondary cyst envelope cells.

Diagnostics spleen cysts

Usually, the diagnosis of a spleen cyst begins with the patient's history and requires a thorough clinical examination.

Blood tests: general clinical and biochemical, for antibodies (IgG) to echinococcus, for serum tumor markers (CEA, CA 19-9).

The main role is played by instrumental diagnostics: ultrasound, CT and / or MRI.

Congenital cysts of the spleen on ultrasound have the appearance of an anechoic mass with smooth walls. Epidermoid cysts have a complex structure with irregularities and thickness of the posterior walls due to epithelial peripheral trabeculae and internal echoes from blood clots. See more details -  ultrasound signs of spleen pathology

Spleen cysts are now known as a rare clinical condition with an incidence of 0.07% in the general population. According to the presence or absence of a lining of the cellular epithelium, these cysts are divided into primary (true) and secondary (false) cysts. Primary cysts are classified as parasitic (60%) and nonparasitic cysts depending on their etiology. Nonparasitic cysts are usually congenital. These cysts are present mainly at a young age and are located in the upper pole of the spleen. [15]

The spleen cyst on CT is visualized in more detail, therefore,  computed tomography of the spleen  helps to determine many parameters of cystic formation and make a more accurate diagnosis. [16]

So, according to localization, there may be a cyst of the upper pole of the spleen (extremitas anterior), protruding forward above the colon; cyst of the posterior pole (extremitas posterior) or on the inside - in the area of the spleen gate (hilum lienis). And with a deeper location - in its pulp or pulp (pulpa splenica) - a cyst in the spleen parenchyma is diagnosed.

The spleen is an encapsulated organ, and a subcapsular cyst of the spleen forms under the tunica fibrosa of the organ.

In addition, a multilocular or multi-chambered cyst of the spleen is often formed, and most often it is an echinococcal cyst.

Differential diagnosis

Differential diagnosis of cysts in the spleen includes its abscess, hemangioma, splenadenoma, lymphangioma, lymphoma, plasmacytoma, reculo and liposarcoma, teratoma. [17]

Treatment spleen cysts

It should be borne in mind that there is no medicine that can "dissolve" the cystic formation. Therefore, the treatment of cysts with a diameter of more than 4 cm is surgical. [18]

Depending on the clinical situation, surgical treatment is carried out by such methods as:

• percutaneous aspiration of contents - laparoscopic puncture of the spleen cyst; [19], [20]
• sclerosing the cyst cavity with ethyl alcohol (after puncture removal of its contents);
• marsupialization (incomplete removal of the mucous membrane of the cyst, cystostomy);
• resection, that is,  removal of the cyst ;
• removal of the affected part of the spleen while preserving at least 30% of its parenchyma. [21]

However, with multiple cysts, with a large cyst in the spleen gate or in the parenchyma, a cyst with dense vascular adhesions with surrounding tissues, experts consider open or laparoscopic splenectomy to be the method of choice  . [22]

If the cyst is not more than 3 cm, then its condition is monitored with annual ultrasound imaging.

Prevention

There is no way to prevent most spleen cysts from forming.

Forecast

For the vast majority of cysts, the prognosis is good, but a spleen cyst larger than 5 cm in diameter has a high risk of rupture, which is fraught with life-threatening intra-abdominal bleeding.