Accessory spleen

An accessory spleen ( Splen accessory, accessory Lien, Splenunculus ) is the result of a common embryological malformation, in which are present one or more small nodules regardless of the spleen, usually in the region of the hilum of spleen tissue in the abdomen. This abnormality must be distinguished from the splenosis, which is the result of a Versprengung of splenic tissue as part of a Milzverletzung.

Epidemiology

Accessory spleens are found in autopsy studies in 10-30 % of cases.

Etiology

Accessory spleens arise as a result of faulty development during the embryonic period. The underlying causes are largely unknown. An increased incidence of intrapancreatic accessory spleens and other developmental anomalies of the spleen 13 ( Patau syndrome) described in trisomy.

Pathology

Macroscopically impress accessory spleens as rounded, usually about cherry size, 1-1.5 cm ( a maximum of about 4 cm) measured, usually limited by a thin capsule masses of dark reddish color. They are predominantly in the area of the splenic hilum (75 % of cases) located, but also along the splenic vessels, in the gastrosplenischen or splenorenal ligaments, the wall of the stomach and intestines, pancreas tail, the mesentery, and rarely also in the pelvic area or scrotum found. A few case reports describe the presence of splenic tissue within the liver parenchyma. Single or multiple accessory spleens come before, but the number exceeds rarely six. Histologically, the construction of an accessory spleen the spleen, that is, the herd shall consist of a red and white pulp together.

Clinic

In most patients, the diagnosis of one or more accessory spleens is an asymptomatic incidental finding without need for therapeutic intervention. Basically, as with the splenosis is a risk that accessory spleens are misinterpreted in diagnostic imaging as a tumor or lymph node swelling. After removal of the spleen ( splenectomy ), as for the treatment of hypersplenism (overactive spleen with abnormally increased Blutzellsequestration ), accessory spleens can take over the function of the spleen in whole or in part, and thus cancel the intended therapeutic effect. A rare acute complication associated with accessory spleens is an acute abdomen due to a Nebenmilzinfarktes with or without torsion of the vascular supply.