An epithelial cyst in an intrapancreatic accessory spleen (ECIAS) is rare. We herein report a case of a patient with ECIAS who underwent laparoscopic surgery. A 57-year-old woman was referred to our hospital because of a pancreatic tail tumor. She was asymptomatic, and a physical examination revealed no remarkable abnormalities. The levels of the tumor marker carbohydrate antigen 19-9 (CA19-9) and s-pancreas-1 antigen (SPan-1) were elevated. Ultrasonography showed a well-defined homogeneous cystic tumor. Computed tomography showed a well-demarcated cystic tumor in the pancreatic tail. Magnetic resonance imaging showed that the cystic tumor exhibited low intensity on T1-weighted images and high intensity on T2-weighted images. The cystic tumor was diagnosed as mucinous cystic neoplasm preoperatively. The patient underwent laparoscopic spleen-preserving distal pancreatectomy. A histopathological examination revealed the cyst wall to be lined by stratified squamous epithelium within splenic parenchyma, and the ultimate diagnosis was ECIAS. The postoperative course was uneventful, and the patient was discharged on postoperative day 12. ECIAS is very difficult to diagnose preoperatively. Laparoscopic surgery is a safe and minimally invasive procedure for patients with difficult-to-diagnose pancreatic tail tumor suspected of having low-grade malignancy.

An accessory spleen is not rare and is observed in 10% of patients at necropsy [1], and 17% of accessory spleens are located within the pancreatic tail [2]. However, an epithelial cyst in an intrapancreatic accessory spleen (ECIAS) is rare. It is very difficult to diagnose preoperatively using conventional imaging such as ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). Therefore, ECIAS is commonly misdiagnosed as other cystic neoplasms, and patients undergo surgical resection. Laparoscopic distal pancreatectomy (Lap-DP) is a safe and minimally invasive procedure and has recently been accepted for benign or low-grade malignant tumors located in the distal pancreas.

We herein report a case of a patient with ECIAS who underwent laparoscopic spleen-preserving distal pancreatectomy (Lap-SPDP) and include bibliographical comments.

A 57-year-old woman was referred to our hospital because a pancreatic tail tumor had been detected during a health examination. She was asymptomatic, and a physical examination revealed no remarkable abnormalities. A laboratory examination showed normal findings. The levels of the tumor marker carbohydrate antigen 19-9 (CA19-9) and s-pancreas-1 antigen (SPan-1) were elevated to 439 U/mL (normal range, <37 U/mL) and 160 U/mL (normal range, <30 U/mL), respectively. US showed a well-defined homogeneous cystic tumor (Fig. 1a). CT showed a well-demarcated cystic tumor measuring 2.2 cm in size in the pancreatic tail (Fig. 1b). MRI showed that the cystic tumor exhibited low intensity on T1-weighted images and high intensity on T2-weighted images (Fig. 1c, d). Based on these preoperative examination findings, the pancreatic tumor was diagnosed as mucinous cystic neoplasm.

Fig. 1.

a Ultrasonography showed a well-defined homogeneous cystic tumor (arrow). b Contrast-enhanced computed tomography showed a well-demarcated cystic tumor measuring 2.2 cm in size in the pancreatic tail (arrow). c, d Magnetic resonance imaging showed that the cystic tumor exhibited low intensity on T1-weighted images (c; arrow) and high intensity on T2-weighted images (d; arrow).

Fig. 1.

a Ultrasonography showed a well-defined homogeneous cystic tumor (arrow). b Contrast-enhanced computed tomography showed a well-demarcated cystic tumor measuring 2.2 cm in size in the pancreatic tail (arrow). c, d Magnetic resonance imaging showed that the cystic tumor exhibited low intensity on T1-weighted images (c; arrow) and high intensity on T2-weighted images (d; arrow).

Close modal

The patient underwent Lap-SPDP. Under general anesthesia, the patient was placed in the right semilateral position. Three trocars were placed: (1) at the middle umbilical site for laparoscopy (12 mm), (2) at the epigastric margin as a working trocar (5 mm), and (3) at the left lateral abdomen on the anterior axillary line as a working trocar (12 mm) (Fig. 2a). Laparoscopic US was performed to confirm the location of the tumor and to determine the resection line of the pancreas. Dissection was performed within the avascular plane along the posterior surface of the pancreas from the inferior border. Many branches of the splenic vessels were divided from the pancreatic body toward the tail using a vessel-sealing device, and the distal pancreas was mobilized (Fig. 2b). The pancreatic parenchyma was transected with an endoscopic linear stapler. After enlarging the middle umbilical site port, the specimen was removed from the abdominal cavity via an endoscopic bag retrieval system. A closed drain was placed at the stump of the pancreas. The operative time was 144 min, and the intraoperative blood loss was 10 mL.

Fig. 2.

a Port placement. b Intraoperative findings.

Fig. 2.

a Port placement. b Intraoperative findings.

Close modal

The resected specimen showed a well-demarcated cystic lesion surrounded with spleen-like tissue (Fig. 3a). A histopathological examination revealed the cyst wall to be lined by stratified squamous epithelium within splenic parenchyma (Fig. 3b). Based on these pathologic findings, the ultimate diagnosis was ECIAS. The postoperative course was uneventful, and the patient was discharged on postoperative day 12. Serum CA19-9 and SPan-1 levels returned to the normal range postoperatively.

Fig. 3.

a The resected specimen showed a well-demarcated cystic lesion surrounded by spleen-like tissue. b A histopathological examination revealed the cyst wall to be lined by stratified squamous epithelium within splenic parenchyma. Hematoxylin-eosin staining. ×40.

Fig. 3.

a The resected specimen showed a well-demarcated cystic lesion surrounded by spleen-like tissue. b A histopathological examination revealed the cyst wall to be lined by stratified squamous epithelium within splenic parenchyma. Hematoxylin-eosin staining. ×40.

Close modal

An accessory spleen is congenitally duplicated splenic tissue that is separated from the main body of the spleen and is observed in 10% of patients at necropsy [1]. The splenic hilum is the most common site of the accessory spleen, and 17% of accessory spleens are located within the pancreatic tail [2]. ECIAS is rare and was first described by Davidson et al. [3] in 1980. Kato et al. [4] summarized their experience with 39 cases of ECIAS in 2016. These cases involved 15 males and 24 females, and the median age was 48 years. All cystic tumors were located in the pancreatic tail. The cystic tumor appeared to be unilocular in 12 cases and multilocular in 21 cases. The average cystic tumor size was 4.5 cm. Wakasugi et al. [5] reported that preoperative serum CA19-9 levels were elevated in 31% of cases.

ECIAS has no malignant potential, so surgical resection for the ECIAS may not be necessary. However, all of these patients underwent surgical resection because the possibility of malignant cystic tumors could not be ruled out. Therefore, an accurate preoperative diagnosis for cystic tumor of the pancreas is important. On US, the solid component of the ECIAS shows the same echogenicity as the spleen. On CT, the cystic wall of the ECIAS shows contrast enhancement similar to that of the spleen during multiphasic scans. On MRI, the solid component of the ECIAS shows the same intensity as that of the spleen, and cystic lesions commonly show low intensity on T1-weighted images and high intensity on T2-weighted images. Few previously reported cases were correctly diagnosed using conventional imaging [6, 7]. In particular, when the amount of accessory splenic tissue is small, accurate preoperative diagnosis by image findings is very difficult. In our case, ECIAS was diagnosed as mucinous cystic neoplasm preoperatively because the amount of accessory splenic tissue was small. An endoscopic US-guided fine needle aspiration (EUS-FNA) biopsy for the differential diagnosis of ECIAS was performed for 4 reported cases [4]. However, a correct pathological diagnosis was not achieved in any of the 4 reported cases, because the amount of solid component was too small to be successfully biopsied by EUS-FNA. In our case, EUS-FNA was not performed for the diagnosis of pancreatic cystic tumor. Therefore, the preoperative diagnosis of the ECIAS is very difficult at present. However, ECIAS should be considered in the differential diagnosis of pancreatic tail cystic tumors.

When it is difficult to diagnose an intrapancreatic cystic tumor, as in our case, and a malignant tumor cannot be completely ruled out, laparoscopic surgery is the better way to avoid the drawbacks of open surgery, such as increased pain and prolonged hospitalization. Lap-DP has recently been accepted for benign or low-grade malignant tumors located in the distal pancreas. There are only 12 reported cases including our own of ECIAS treated by laparoscopic surgery in the English literature (Table 1) [4-13]. In these cases, the median age of the patients was 50 years (range, 21–67 years) and included 3 males and 9 females. The median tumor size was 2.8 cm (range, 1.5–5 cm). The median operative time was 204 min (range, 140–278 min), and the median blood loss was 50 mL (range, 10–400 mL). The median postoperative hospital stay was 12 days (range, 3–21 days). In our case, it was thought that laparoscopic surgery was a safe and minimally invasive procedure for the patient because there was a short operative time, little blood loss, and no postoperative complication. Lap-DP and Lap-SPDP have been performed in 6 patients each. We performed Lap-SPDP because the immunological role of the spleen has been increasingly emphasized and the preservation of the spleen is preferable to avoid long-term complications associated with splenectomy [14].

Table 1.

Reported laparoscopic surgical cases of an epithelial cyst in an intrapancreatic accessory spleen

Reported laparoscopic surgical cases of an epithelial cyst in an intrapancreatic accessory spleen
Reported laparoscopic surgical cases of an epithelial cyst in an intrapancreatic accessory spleen

ECIAS is rare and very difficult to accurately diagnose preoperatively. Laparoscopic surgery is a safe and minimally invasive procedure for patients with difficult-to-diagnose pancreatic tail tumor suspected of having low-grade malignancy.

Approval from the ethics committee was not required for this case report. Written informed consent was obtained from the patient for publication of this case report and any accompanying images.

None of the authors has any financial conflicts of interest to declare.

1.
Halpert B, Alden ZA: Accessory spleen in or at the tail of the pancreas. A survey of 2,700 additional necropsies. Arch Pathol 1964; 77: 652–654.
2.
Halpert B, Gyorkey F: Lesions observed in accessory spleens of 311 patients. Am J Clin Pathol 1959; 32: 165–168.
3.
Davidson ED, Campbell WG, Hersh T: Epidermoid splenic cyst occurring in an intrapancreatic accessory spleen. Dig Dis Sci 1980; 25: 964–967.
4.
Kato S, Mori H, Zakimi M, Yamada K, Chinen K, Arashiro M, Shinoura S, Kikuchi K, Murakami T, Kunishima F: Epidermoid cyst in an intrapancreatic accessory spleen: case report and literature review of the preoperative imaging findings. Intern Med 2016; 55: 3445–3452.
5.
Wakasugi M, Tori M, Akamatsu H, Ueshima S, Omori T, Tei M, Masuzawa T, Tsujimoto M, Nishida T: Laparoscopic distal pancreatectomy for multiple epithelial cysts in an intrapancreatic accessory spleen. A case report and review of literature. JOP 2013; 14: 636–641.
6.
Itano O, Shiraga N, Kouda E, Iri H, Tanaka K, Hattori H, Suzuki F, Otaka H: Epidermoid cyst originating from an intrapancreatic accessory spleen. J Hepatobiliary Pancreat Surg 2008; 15: 436–439.
7.
Urakami A, Yoshida K, Hirabayashi Y, Kubota H, Yamashita K, Hirai T, Tsunoda T: Laparoscopy-assisted spleen-preserving pancreatic resection for epidermoid cyst in an intrapancreatic accessory spleen. Asian J Endosc Surg 2011; 4: 185–188.
8.
Iwasaki Y, Tagaya N, Nakagawa A, Kita J, Imura J, Fujimori T, Kubota K: Laparoscopic resection of epidermoid cyst arising from an intrapancreatic accessory spleen: a case report with a review of the literature. Surg Laparosc Endosc Percutan Tech 2011; 21:e275–e279.
9.
Khashab MA, Canto MI, Singh VK, Hruban RH, Makary MA, Giday S: Endosonographic and elastographic features of a rare epidermoid cyst of an intrapancreatic accessory spleen. Endoscopy 2011; 43(suppl 2):E193–E194.
10.
Panagiotopoulos N, Acharya M, Ahmad R, Bansi D, Jiao L: Epithelial inclusion cyst arising within an intra-pancreatic splenunculus. Int J Surg Case Rep 2012; 3: 118–120.
11.
Harris AC, Chaudry MA, Menzies D, Conn PC: Laparoscopic resection of an epidermoid cyst within an intrapancreatic accessory spleen: a case report and review article. Surg Laparosc Endosc Percutan Tech 2012; 22:e246–e249.
12.
Kwak MK, Lee NK, Kim S, Han GJ, Seo HI, Park DY, Lee SJ, Kim TU: A case of epidermoid cyst in an intrapancreatic accessory spleen mimicking pancreas neoplasms: MRI with DWI. Clin Imaging 2016; 40: 164–166.
13.
Fujii M, Yoshioka M, Shiode J: Two cases of an epidermoid cyst developing in an intrapancreatic accessory spleen identified during laparoscopic distal pancreatectomy. Intern Med 2016; 55: 3137–3141.
14.
Cullingford GL, Watkins DN, Watts AD, Mallon DF: Severe late postsplenectomy infection. Br J Surg 1991; 78: 716–721.
Open Access License / Drug Dosage / Disclaimer
This article is licensed under the Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC). Usage and distribution for commercial purposes requires written permission. Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug. Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.