ORIGINAL COMMUNICATION

Accessory Spleens at Autopsy

NADIRE UNVER DOGAN,1* ISMIHAN ILKNUR UYSAL,1 SERAFETTIN DEMIRCI,2

KAMIL HAKAN DOGAN,2 AND GIRAY KOLCU2

1Department of Anatomy, Selcuklu Medical School, Selcuk University, Konya, Turkey2Department of Forensic Medicine, Meram Medical School, Selcuk University, Konya, Turkey

Accessory spleens (AS) may be formed during embryonic development whensome of the cells from the developing spleen are deposited along the pathfrom the midline, where the spleen forms, over to its final location on the leftside of the abdomen. An accessory spleen is usually near the spleen’s hilum,but it may be embedded partly or wholly in the tail of the pancreas. The aim ofthis study was to investigate the incidence and distribution of AS during rou-tine forensic autopsies. AS were investigated in 720 consecutive autopsycases. Fifty-four AS were found in 48 (6.7%) cases. AS were found in hilum ofthe main spleen in 28 cases, the great omentum in 13 cases, the pancreas in 5cases, and the pelvis in 2 cases. There were two AS in two cases and three ASin another two cases. Awareness of the possible presence of AS is importantbecause when splenectomy is performed for some conditions such as immunethrombocytopenic purpura, failure to remove the AS may result in the failureof the condition to resolve. Additionally, during medical imaging, AS may beconfused for enlarged lymph nodes or neoplastic growths. In conclusion, au-topsy series are useful for determining the incidences and the other featuresof AS in different populations, in addition to those studies using CT scans andthose studies obtained during laparoscopic or open surgeries. Clin. Anat.24:757–762, 2011. VVC 2011 Wiley-Liss, Inc.

Key words: accessory spleen; anatomy; spleen; autopsy

INTRODUCTION

The spleen consists of a large encapsulated massof vascular and lymphoid tissue situated in the upperleft quadrant of the abdominal cavity betweenthe fundus of the stomach and the diaphragm(Standring, 2005). It contacts the posterior wall ofthe stomach and is connected to the greater curva-ture by the gastrosplenic (gastrolienal) ligament andto the left kidney by the splenorenal (lienorenal) lig-ament (Moore, 1992).

The spleen appears at approximately the sixth weekof embryologic life as a localized thickening of the coe-lomic epithelium of the dorsal mesogastrium near itscranial end. The proliferating cells invade the underly-ing angiogenetic mesenchyme, which becomescondensed and vascularized. The process occurssimultaneously in several adjoining areas, which soonfuse to form a lobulated spleen. In the subsequent

periods of embryologic life, the earlier lobulated char-acter of the spleen disappears but is indicated by thepresence of notches on its upper border in the adult.The spleen can display various developmental anoma-lies, including complete agenesis, multiple spleens orpolysplenia, isolated small additional splenunculi, andpersistent lobulation (Standring, 2005).

Accessory spleens (AS) may be formed duringembryonic development as ectopic or separatedsplenic tissue along the path from where the spleen

*Correspondence to: Dr. Nadire Unver Dogan, Department ofAnatomy, Selcuklu Medical Faculty, Selcuk University, 42075Konya, Turkey. E-mail: nunver2003@yahoo.com

Received 25 August 2010; Revised 5 December 2010;Accepted 10 January 2011

Published online 3 March 2011 in Wiley Online Library(wileyonlinelibrary.com). DOI 10.1002/ca.21146

VVC 2011 Wiley-Liss, Inc.

Clinical Anatomy 24:757–762 (2011)

forms at the midline to the spleen’s final location onthe left side of the abdomen (Moore and Persaud,1993; Standring, 2005).

The aim of this study was to investigate the inci-dence and distribution of AS during routine forensicautopsies.

MATERIALS AND METHODS

Prior to beginning this prospective study, formswere prepared to collect data about AS. Data wascollected from 720 consecutive Anatolian medicole-gal autopsies performed by forensic pathologistsbetween 2005 and 2007 at The Konya Branch ofForensic Medicine Council (Turkey) and in the dis-tricts of Konya. While they were examining thespecimens for disposition of the structures andorgans of the abdomen, these same forensic patho-logists (S.D. and K.H.D.) looked for accessoryspleens in the abdomen. Sites examined for theappearance of accessory spleens were in the hilumof the main spleen, the tail of the pancreas, greateromentum, and in the pelvis. If accessory spleenswere found, the prepared forms were filled out foreach of the cases.

The cases of AS were evaluated in terms of theirdemographic features, localization, number, shape(round, ovoid, triangular), and size (greatest diame-ter). None of the cases had any hematologic disor-ders or splenomegaly. None of the subjects hadundergone a splenectomy or other surgery thatmight possibly damage the spleen and none of themhad a history of trauma to the main spleen.

RESULTS

Incidence and Demographic Features

Fifty-four AS were found in 48 (6.7%) cases.These cases were aged from 3 months to 62 yearsand the ratio of males to females was 1.5:1. Therewas one AS in 44 cases, two AS in 2 cases and threeAS in another 2 cases.

Localization

The distribution of the 54 total AS is given inFigure 1. Twenty-eight (51.9%) of the AS werefound near the hilum of the main spleen, 13(24.1%) of them in the greater omentum (Fig. 2),5 (9.3%) of them within the tail of the pancreas(Figs. 3 and 4), 3 (5.5%) of them in the gastro-splenic ligament (Fig. 4), 3 (5.5%) of them in thesplenorenal ligament, and 2 (3.7%) of them in thepelvis (Fig. 5).

Shape and Size

Forty-four (81.5%) AS were round, eight (14.8%)were ovoid, and two (3.7%) were triangular inshape. The greatest diameter of the AS rangedbetween 0.5 and 2.8 cm, and the mean greatest di-ameter was 1.6 cm.

DISCUSSION

AS are also known as ‘‘splenules’’ or ‘‘splenunculi.’’Many authors reported an incidence rate between 10and 30% especially in patients undergoing splenec-tomy for hematologic diseases (Halpert and Gyorkey,1959; Beahrs and Stephens, 1980; Dodds et al.,1990; Freeman et al., 1993; Brunt et al., 1996; Glas-gow et al., 1997). Park et al. (1999) reported an inci-dence rate of 15.0% for AS in patients undergoinglaparoscopic splenectomy for different hematologicdiseases. The largest series of CT studies was per-formed by Mortele et al. (2004). They used contrast-enhanced CT imaging and they reported that a 2-mmsize accessory spleen can be determined by contrast-enhanced CT. There is a lack of prospective consecu-tive autopsy series studies for determining the inci-dence of AS in different populations in the literature.In this study, the rate of AS was 6.7% within the inci-dence range (4.0–15.6%) reported in the literaturepublished in the last 15 years which were performedby open and laparoscopic surgery, CT scans, or fetusdissections (Table 1).

The reported frequencies for one, two and threeAS have been reported as 79–86%, 10.5–14%, and1–10.5%, respectively (Mortele et al., 2004; Mendiet al., 2006; Ungor et al., 2007). In this study, oneaccessory spleen was the most common (91.6%),consistent with the literature.

AS are usually near the spleen’s hilum, but theymay be embedded partly or wholly in the tail of thepancreas (Moore, 1992), in the greater omentum(Standring, 2005), in the wall of the stomach orbowel, in the mesentery or even in the pelvis andscrotum (Sty and Conway, 1985; Hayward et al.,1992; Moore, 1992; Gayer et al., 2001; Standring,2005). They are usually about 1 cm in diameterbut vary from microscopic deposits not visible on

Fig. 1. The distribution of accessory spleens (n¼ 54).

758 Unver Dogan et al.

Fig. 2. An accessory spleen (:) in the greater omentum in a 25-year-oldwoman. [Color figure can be viewed in the online issue, which is available atwileyonlinelibrary.com.]

Fig. 3. An accessory spleen (:) embedded in the tail of the pancreas in a 32-year-old man. [Color figure can be viewed in the online issue, which is available atwileyonlinelibrary.com.]

759Accessory Spleens at Autopsy

Fig. 4. Two accessory spleens (:) in a 3-year-old girl. One of them is embeddedin the tail of the pancreas, the other one is in the gastrosplenic ligament. [Color fig-ure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

Fig. 5. An accessory spleen (:) in the pelvis in a 36-year-old woman. [Color fig-ure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

760 Unver Dogan et al.

CT to 5 cm in diameter (Koehler, 1989; Moore, 1992;Moore and Persaud, 1993; Coote et al., 1999; Mendiet al., 2006). AS were found mostly (51.9%) near thehilum of the main spleen, and the greatest diameterof the AS ranged between 0.5 and 2.8 cm (meangreatest diameter, 1.6 cm) in this study.

One of the most comprehensive studies about ASwas performed by Mortele et al. (2004) on abdomi-nal contrast-enhanced CT scans of 1,000 consecutivepatients. Of these patients, 156 (15.6%) had at leastone accessory spleen, and 21 of these patients(13%) had more than one accessory spleen (two orthree), resulting in a total of 180 AS. Their meananteroposterior diameter was 11.9 mm. Their meantransverse diameter was 11.6 mm. The shape of ASwas round in 141 patients (78.3%), ovoid in 27(15%), and triangular in 12 (6.7%). The localizationof AS in that study was variable. All of the AS werein the left upper quadrant of the abdomen and themost common localization was the inferior third ofthe posteromedial compartment of the left upperquadrant (21.8%). In two patients, intrapancreaticaccessory spleen was found. However, they did notimage the pelvis in their study population. In ourstudy, there were five intrapancreatic AS and twointrapelvic AS. In addition, 81.5% of AS were round,14.8% were ovoid, and 3.7% were triangular inshape, similar to the findings of Mortele et al.

The studies on AS have been generally performedon CT images of adult patients. In a study of fetalAS, Ungor et al. (2007) detected 25 AS in 19 (14%)of 141 fetuses. Of these 25 AS, 16 (64%) werelocated in the splenic hilum, 3 (12%) were in thegastrosplenic ligament, 3 (12%) were in the sple-norenal ligament, 1 (4%) was near the pancreas tail,1 (4%) was near the stomach, and 1 (4%) was inthe great omentum. Similarly, most of the AS(51.9%) were in the splenic hilum in this study.

Awareness of the presence of an accessory spleenis important in a patient evaluated by CT prior tosplenectomy, as failure to remove it may result inpersistence of the condition that indicated the needfor splenectomy (Moore, 1992; Gayer et al., 2001).An accessory spleen may be of clinical importance asa source of ‘‘preservable’’ splenic tissue in cases of aruptured primary spleen. Additionally, during medi-cal imaging, AS may be confused for enlarged lymphnodes or neoplastic growths.

An AS is an incidental finding of no clinical signifi-cance in most patients. AS are generally determinedduring radiological investigations or during open orlaparoscopic surgeries (Yee et al., 1995). AS areusually asymptomatic, but they are rarely reported

to present clinically as an abdominal mass related tocomplications such as torsion, spontaneous rupture,hemorrhage, and cyst formation. Torsion and ische-mia of AS can lead to gangrene, abscess, peritonitis,and can present as an acute abdomen, as seen intorsion of the main spleen (Valls et al., 1998; Cooteet al., 1999; Padilla et al., 1999; Grinbaum et al.,2006; Mendi et al., 2006).

The European Association of Endoscopic Surgeryhas recommended a routine search for AS intraoper-atively along with preoperative CT scan to achievethe highest detection rates and to prevent diseaserecurrence, especially for autoimmune hematologicaldisorders. However, the value of preoperative imag-ing to detect AS remains unclear (Quah et al.,2010). Some researchers report that the sensitivityof detecting AS with preoperative CT is higher (Gigotet al., 1998; Napoli et al., 2004), but others reportthat laparoscopy has a higher sensitivity (Staneket al., 2005; Quah et al., 2010). Quah et al. (2010)recently reported that the sensitivity of CT scanbefore laparoscopic splenectomy in detecting AS was60%, whereas the sensitivity of laparoscopy indetecting AS was 93%. It was also reported that Tc-99m heat denatured red blood cell SPECT techniqueand reticuloendothelial system-specific contrast-enhanced MRI may be used for detecting AS (Phomet al., 2001; Boraschi et al., 2005).

During laparoscopic exploration, AS are routinelysearched for in the splenic hilum, the great omentum,and the left paracolic space, as well as in the lieno-colic, splenorenal, and gastrocolic ligaments; thelesser sac and the tail of the pancreas (Rudowski,1985; Gigot et al., 1998). A handheld gamma probeis a useful and successful adjunct to localization andremoval of AS (Bergeron et al., 2008). In this study,although the most common localizations of AS werethe regions that are routinely searched to detect ASin laparoscopic splenectomy (96.3%), 3.7% of the ASwere detected in the pelvis. As pelvis and scrotum arereported as localizations for AS, surgeons shouldkeep these atypical localizations in mind.

CONCLUSION

The incidence and morphological and morphomet-ric features of AS in 720 consecutive Anatolian au-topsy cases are evaluated in this prospective study.The most important limitation of this study was thatthe determination of AS in these autopsies was per-formed only macroscopically. In addition, AS in thescrotum could not be determined because the scro-

TABLE 1. The Incidence of AS in Different Studies

Author Country No. of cases Method Incidence (%)

Yee et al. (1995) USA 25 Laparoscopic surgery 4.0Winde et al. (1996) Germany 72 Open surgery 4.2Park et al. (1999) USA 147 Laparoscopic surgery 15.0Mortele et al. (2004) Belgium 1,000 CT scans 15.6Casaccia et al. (2006) Italy 309 Laparoscopic surgery 8.1Ungor et al. (2007) Turkey 141 Fetus dissections 13.5This study Turkey 720 Autopsy cases 6.7

761Accessory Spleens at Autopsy

tum was not dissected during routine autopsies. Thelocalizations and the morphological and morphomet-ric features of the AS were determined in detail, andthe AS were photographed. It is concluded that, inaddition to studies on CT scans and laparoscopic oropen surgery series, autopsy series are useful fordetermining the incidences and the other features ofAS in different populations.

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