The spleen develops from mesenchymal tissue in the dorsal mesogastrium during the fifth week of fetal life. An accessory spleen may arise from incomplete fusion of these mesenchymal buds.[5,7] Because the spleen originates in the dorsal mesogastrium and then rotates to the left side of the abdomen, accessory spleens are always located in the left side of the body. The most common sites of accessory spleens are in the splenic hilum (75%) and in the pancreatic tail (20%), the remaining 5% of the sites include the gastrosplenic ligament, splenocolic and gastrocolic ligaments, splenic artery, greater omentum, mesenterium, left scrotum, and mediastinum.[2,3,7,8] Accessory spleens generally range in size from 2 to 4 cm and receive blood supply from the branches of the splenic artery; only a few cases of large accessory spleen more than 10 cm in size have been reported.[6,9,10] In our case, the patient had large accessory spleen.
Accessory spleen torsion is a rare entity, and only 31 cases (including this case) were reported in English literatures.[1–28] Torsion of an accessory spleen generally presents as nonspecific acute abdominal pain, some of which is accompanied by fever, nausea, vomiting, leukocytosis, and ascites. These clinical manifestations are related to 3 features: First, torsion of an accessory spleen will undergo infarction and strangulation, producing acute inflammation.[6,11] Second, twisting of the vascular pedicle results in venous congestion, causing enlargement and swelling of the accessory spleen. Third, direct mechanical interference to adjacent organs. All 3 of these features were observed in our case. Although there was no evidence of relationship between size, origin, and torsion, exercise may be a cause of accessory spleen torsion in this case.
Other complications of accessory spleen torsion are even rare, such as spontaneous rupture and hemorrhagic shock, infection and peritonitis, and intestinal obstruction. Only 1 case of intestinal obstruction caused by accessory spleen torsion was reported previously in which small bowel and colon were adherent to accessory spleen. However, our case is distinct because accessory spleen torsion pressured against splenic flexure and descending colon, and caused mechanical colon obstruction. This presentation may relate to the enlargement of accessory spleen due to venous congestion and the location approaching to splenic flexure and descending colon.
Interestingly, systemic inflammatory response syndrome (SIRS) was observed in the patient, whose body temperature was 38.5°C (>38°C), heart rate was 135 beats/min (>90 beats/min), respiratory rate was 25 breaths/min (>20 breaths/min), the white blood cell count was 18,400 cells/mm3 (>12,000 cells/mm3). These clinical parameters fulfilled all 4 SIRS criteria recommended by the American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference. To the best of our knowledge, this is the first report of SIRS in such cases. We cannot completely explain the clinical presentation. Nonetheless, the presentation of SIRS is likely to be related to intestinal obstruction with resultant bacterial translocation (BT)  and accessory spleen infarction with resultant inflammatory changes. Many studies have shown that BT or gut-derived factors may provoke SIRS.[31,32]
Preoperative diagnosis of accessory spleen torsion is very difficult, even with the modern imaging tools. Abdominal CT and ultrasonography examinations are helpful to make diagnosis. CT scan may disclose the mass and evaluate the shape, size, and changes of surrounding tissues, and contrast-enhanced CT may reveal a hypodense mass with peripheral enhancement. However, it is impossible to make accurate diagnosis unless a twisted vascular pedicle can be found. Ultrasonography findings include a well-defined, hypoechoic, and homogeneous mass. Doppler ultrasonography may confirm the avascular nature, but cannot distinguish between a cystic mass and accessory spleen torsion. Magnetic resonance imaging (MRI), scintigraphy and angiography can provide significant information, but they are not always available in an emergency condition.[7,15] In our case, emergency laparotomy was performed to arrest strangulated intestinal obstruction and avoid the progression to multiple organ dysfunction syndrome (MODS) from SIRS. There was not enough time to perform contrast-enhanced CT, MRI, scintigraphy, and angiography.
Differential diagnosis should be considered preoperatively. A presumptive diagnosis of intraperitoneal tumor was made due to routine CT and ultrasonography revealing soft tissue mass. Enhanced CT might establish the nature of the mass but was of unknown origin. Intussusception was suspected because of abdominal mass and intestinal obstruction, but a target or sandwich sign on ultrasonography and a targetlike appearance on CT scan may confirm the diagnosis of intussusception. Abscess was another possibility, which appeared as a hypoattenuating lesion on CT scan and the presence of gas was typical CT findings.
In conclusion, accessory spleen torsion and its complications, such as intestinal obstruction, are extremely rare. It is very difficult to make an accurate diagnosis preoperatively. This entity should be considered in differential diagnosis of acute abdomen. However, in case of acute abdomen with critical clinical situation, emergency surgical intervention is necessary for timely diagnosis and treatment.
. Alexander RC, Romanes A. Accessory spleen causing acute attacks of abdominal pain. Lancet 1914;184:1089–91.
. Gardakis S, Pitiakoudis M, Sigalas I, et al. Infarction of an accessory spleen presenting as acute abdomen in a neonate. Eur J Pediatr Surg 2005;15:203–5.
. Settle EB. The surgical importance of accessory spleens: with report of two cases. Am J Surg 1940;50:22–6.
. Babcock TL, Coker DD, Haynes JL, et al. Infarction of an accessory spleen causing an acute abdomen. Am J Surg 1974;127:336–7.
. Padilla D, Ramia JM, Martin J, et al. Acute abdomen due to spontaneous torsion of an accessory spleen. Am J Emerg Med 1999;17:429–30.
. Kitchin RJ, Green NA. Torsion of an accessory spleen presenting as acute appendicitis. Br J Surg 1962;50:232–3.
. Grinbaum R, Zamir O, Fields S, et al. Torsion of an accessory spleen. Abdom Imaging 2006;31:110–2.
. Wacha M, Danis J, Wayand W. Laparoscopic resection of an accessory spleen in a patient with chronic lower abdominal pain. Surg Endosc 2002;16:1242–3.
. Perez Fontan FJ, Soler R, Santos M, et al. Accessory spleen torsion: US, CT and MR findings. Eur Radiol 2001;11:509–12.
. Bard V, Goldberg N, Kashtan H. Torsion of a huge accessory spleen in a 20-year-old patient. Int J Surg Case Reports 2014;5:67–9.
. Seo T, Ito T, Watanabe Y, et al. Torsion of an accessory spleen presenting as an acute abdomen with an inflammatory mass. US, CT, and MRI findings. Pediatr Radiol 1994;24:532–4.
. Valls C, Monés L, Gumà A, et al. Torsion of a wandering accessory spleen: CT findings. Abdom Imaging 1998;23:194–5.
. Mendi R, Abramson LP, Pillai SB, et al. Evolution of the CT imaging findings of accessory spleen infarction. Pediatr Radiol 2006;36:1319–22.
. Impellizzeri P, Montalto AS, Borruto FA, et al. Accessory spleen torsion: rare cause of acute abdomen in children and review of literature. J Pediatr Surg 2009;44:E15–8.
. Jans R, Vanslembrouck R, Van-Hoe L, et al. Torsion of accessory spleen in an adult patient: imaging findings at CT, MRI and angiography. J Belge Radiol 1997;80:229–30.
. Alexander RC. Accessory spleen with recurring torsion of its pedicle. Lancet 1929;2:29.
. Hems TEJ, Bellringer JF. Torsion of an accessory spleen in an elderly patient. Postgrad Med J 1990;66:838–9.
. Dahlin LB, Agagnostaki L, Delshammar M, et al. Torsion of an accessory spleen in an adult. Case report. Eur J Surg 1995;161:607–9.
. Corsi A, Summa A, De Filippo M, et al. Acute abdomen in torsion of accessory spleen. Eur J Radiol Extra 2007;64:15–7.
. Zhang KR, Jia HM. Symptomatic accessory spleen. Surgery 2008;144:476–7.
. Kim TH, Kim JK, Park MJ, et al. Education and imaging. Hepatobiliary and pancreatic: torsion of an accessory spleen. J Gastroenterol Hepatol 2009;24:1308.
. Yousef Y, Cameron BH, Maizlin ZV, et al. Laparoscopic excision of infarcted accessory spleen. J Laparoendosc Adv Surg Tech A 2010;20:301–3.
. Ishibashi H, Oshio T, Sogami T, et al. Torsion of an accessory spleen with situs inversus in a child. J Med Invest 2012;59:220–3.
. Sadro CT, Lehnert BE. Torsion of an accessory spleen: Case report and review of the literature. Radiol Case Rep 2013;8:802.
. Lhuaire M, Sommacale D, Piardi T, et al. A rare cause of chronic abdominal pain: recurrent sub-torsions of an accessory spleen. J Gastrointest Surg 2013;17:1893–6.
. Mocanu SN, Sierra Vinuesa A, Muñoz-Ramos Trayter C, et al. Accessory spleen torsion in a teenager. ANZ J Surg 2015;85:987–9.
. Ozeki M, Asakuma M, Go N, et al. Torsion of an accessory spleen: a rare case preoperatively diagnosed and cured by single-port surgery. Surg Case Rep 2015;1:100.
. Bass RT, Tao Yao S, Freeark RJ. Torsion of an accessory spleen of the cecum presenting as acute appendicitis. New Engl J Med 1967;277:1190–1.
. American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference. Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. Crit Care Med 1992;20:864–74.
. Sagar PM, MacFie J, Sedman P, et al. Intestinal obstruction promotes gut translocation of bacteria. Dis Colon Rectum 1995;38:640–4.
. Deitch EA, Xu D, Kaise VL. Role of the gut in the development of injury- and shock induced SIRS and MODS: the gut-lymph hypothesis, a review. Front Biosci 2006;11:520–8.
. Shiomi H, Shimizu T, Endo Y, et al. Relations among circulating monocytes, dendritic cells, and bacterial translocation in patients with intestinal obstruction. World J Surg 2007;31:1806–12.
. Haga Y, Beppu T, Doi K, et al. Systemic inflammatory response syndrome and organ dysfunction following gastrointestinal surgery. Crit Care Med 1997;25:1994–2000.