Splenosis is the result of

spleen The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes .

tissue breaking off the main organ and implanting at another site inside the body. This is called '' heterotopic autotransplantation'' of the spleen. It most commonly occurs as a result of traumatic

splenic rupture A splenic injury, which includes a ruptured spleen, is any injury to the spleen. The rupture of a normal spleen can be caused by trauma, such as a traffic collision. Signs and symptoms In minor injuries with little bleeding, there may be abdomin ...

abdominal surgery The term abdominal surgery broadly covers Surgery, surgical procedures that involve opening the abdomen (laparotomy). Surgery of each abdominal organ is dealt with separately in connection with the description of that organ (see stomach, kidney, l ...

. Depending on the location of the spleen, the new piece usually implants in another part of the

abdominal cavity The abdominal cavity is a large body cavity in humans and many other animals that contains many organs. It is a part of the abdominopelvic cavity. It is located below the thoracic cavity, and above the pelvic cavity. Its dome-shaped roof is the th ...

(including the

pelvic cavity The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily contains the reproducti ...

). Single case reports also describe splenosis in the

thoracic cavity The thoracic cavity (or chest cavity) is the chamber of the body of vertebrates that is protected by the thoracic wall (rib cage and associated skin, muscle, and fascia). The central compartment of the thoracic cavity is the mediastinum. There ...

, in

subcutaneous tissue The subcutaneous tissue (), also called the hypodermis, hypoderm (), subcutis, superficial fascia, is the lowermost layer of the integumentary system in vertebrates. The types of cells found in the layer are fibroblasts, adipose cells, and macr ...

, in the

liver The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for ...

or in the

cranial cavity The cranial cavity, also known as intracranial space, is the space within the skull that accommodates the brain. The skull minus the mandible is called the ''cranium''. The cavity is formed by eight cranial bones known as the neurocranium that in ...

. Splenosis must be distinguished from the presence of additional spleens, which are innate and are the result of differences in embryological development. Additionally, splenosis must be differentiated from malignant tumors which may look similar when imaged.R. D. Fremont, T. W. Rice: ''Splenosis: A Review.''

History

Ectopic splenic tissue was first described in 1896 by Albrecht in Germany, whereas the term “splenosis” was first used by Buchbinder and Lipkoffin to describe their findings in 1939

Cause

A necessary requirement for splenosis is the rupture of the spleen, through a

traumatic injury An injury is any physiological damage to living tissue caused by immediate physical stress. An injury can occur intentionally or unintentionally and may be caused by blunt trauma, penetrating trauma, burning, toxic exposure, asphyxiation, or o ...

(such as a car wreck) or

, especially

splenectomy A splenectomy is the surgical procedure that partially or completely removes the spleen. The spleen is an important organ in regard to immunological function due to its ability to efficiently destroy encapsulated bacteria. Therefore, removal of ...

. Splenosis in the abdominal category may occur in up to 65% of traumatic ruptures of the spleen. Splenosis in the thoracic cavity is rarer, because it requires the simultaneous rupture of the diaphragm. The implantation of spleen tissue under the skin may result from abdominal surgery or

gunshot wound A gunshot wound (GSW) is a penetrating injury caused by a projectile (e.g. a bullet) from a gun (typically firearm or air gun). Damages may include bleeding, bone fractures, organ damage, wound infection, loss of the ability to move part of th ...

s. Splenosis of the brain or liver is hypothesized to be the result of tiny pieces of spleen tissue traveling through the bloodstream.

Pathology

Macroscopically, splenosis manifests as individual pieces of reddish-blue tissue with variable shape, which can be as few as one and as many as 300, mostly in the abdominal cavity, and varying in size from a few millimeters to as large as 12 cm. Due to the limited blood supply to these nodules, the typical size of splenic implants is usually less than 3 cm. The implants can be separate pieces or connect to other pieces of splenic tissue by a thin stem.

Histologically Histology, also known as microscopic anatomy or microanatomy, is the branch of biology Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single ...

, the regular spleen tissue is made up of red and white pulp, similar to the structure of an accessory spleen.

Clinical presentation

About a decade commonly passes between the injury and the discovery of splenosis. As little as five months and as much as 32 years have been reported. Most people with splenosis have no symptoms, so the splenosis is discovered by chance through

screening Screening may refer to: * Screening cultures, a type a medical test that is done to find an infection * Screening (economics), a strategy of combating adverse selection (includes sorting resumes to select employees) * Screening (environmental), a ...

or in the process of diagnosing another disease. Some people experience symptoms, such as

abdominal pain Abdominal pain, also known as a stomach ache, is a symptom Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than ...

intestinal obstruction Bowel obstruction, also known as intestinal obstruction, is a mechanical or functional obstruction of the intestines which prevents the normal movement of the products of digestion. Either the small bowel or large bowel may be affected. Signs an ...

, hemorrhage, or

hydronephrosis Hydronephrosis describes hydrostatic dilation of the renal pelvis and calyces as a result of obstruction to urine flow downstream. Alternatively, hydroureter describes the dilation of the ureter, and hydronephroureter describes the dilation of t ...

. Tissue infarction due to limited blood supply can be a cause of symptomatic splenosis.{{Cite journal, last=Widmann, first=MAJ Warren D., date=1971-02-01, title=Splenosis: A Disease or a Beneficial Condition?, journal=Archives of Surgery, language=en, volume=102, issue=2, pages=152–8, doi=10.1001/archsurg.1971.01350020062018, pmid=5101334, issn=0004-0010 Symptoms of splenosis affecting the thoracic cavity sometimes include

hemoptysis Hemoptysis is the coughing up of blood or blood-stained mucus from the bronchi, larynx, trachea, or lungs. In other words, it is the airway bleeding. This can occur with lung cancer, infections such as tuberculosis, bronchitis, or pneumonia, and ...

pleurisy Pleurisy, also known as pleuritis, is inflammation of the membranes that surround the lungs and line the chest cavity (pleurae). This can result in a sharp chest pain while breathing. Occasionally the pain may be a constant dull ache. Other sy ...

Diagnosis

A definitive diagnosis is often made through biopsy and histological examination of the tissue by a

pathologist Pathology is the study of the causal, causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when us ...

. Multiple implants of splenic tissue can mimic the appearance of some cancerous conditions. This can be clarified through diagnostic imaging (for example, ultrasound, CT scan, and MRI). In particular, splenosis is differentiated from different forms of

lymphoma Lymphoma is a group of blood and lymph tumors that develop from lymphocytes (a type of white blood cell). In current usage the name usually refers to just the cancerous versions rather than all such tumours. Signs and symptoms may include enlar ...

, metastisized cancers, cancer of the abdomen and pleural tissues, primary kidney or liver tumors,

endometriosis Endometriosis is a disease of the female reproductive system in which cells similar to those in the endometrium, the layer of tissue that normally covers the inside of the uterus, grow outside the uterus. Most often this is on the ovaries, f ...

or non-cancerous

swollen lymph nodes Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels tight, the area ma ...

Treatment

Treatment of splenosis is often unnecessary, because it is

benign Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malign ...

and usually asymptomatic. For people experiencing symptoms, the splenic tissue can be removed by surgery.

Epidemiology

Splenosis is slightly more common in males than females, probably due to the greater frequency of physical trauma experienced by men.J. N. Yammine, A. Yatim, A. Barbari: ''Radionuclide imaging in thoracic splenosis and a review of the literature.''

References

Spleen (anatomy) Diseases of spleen