Wakasugi M, et al. Laparoscopic Distal Pancreatectomy for Multiple Epithelial Cysts in an Intrapancreatic Accessory Spleen. A Case Report and Review of Literature. JOP. J Pancreas (Online) 2013 Nov 10; 14(6):636-641.

CASE REPORT

JOP. J Pancreas (Online) 2013 Nov 10; 14(6):636-641.

Laparoscopic Distal Pancreatectomy for Multiple Epithelial Cysts in an Intrapancreatic Accessory Spleen. A Case Report and Review of Literature

Masaki Wakasugi¹, Masayuki Tori¹, Hiroki Akamatsu¹, Shigeyuki Ueshima¹, Takeshi Omori¹, Mitsuyoshi Tei¹, Toru Masuzawa¹, Masahiko Tsujimoto², Toshirou Nishida¹

Departments of ¹Surgery and ²Pathology, Osaka Police Hospital. Osaka, Japan

ABSTRACT

Context Accessory spleen is a congenital abnormality consisting of normal splenic tissue in ectopic sites that is found in approximately 10-15% of the general population. However, an intrapancreatic accessory spleen has seldom been reported and multiple epithelial cysts in the intrapancreatic accessory spleen are extremely rare. Case report A 37-year-old woman with no clinical manifestations presented with two cystic lesions in the tail of the pancreas. The tumor markers CA 19-9 (251 U/mL) and SPAN-1 (38 U/mL) were increased. Computed tomography showed a multilocular cyst, 40 mm in size, and a unilocular cyst, 20 mm in size, in the tail of the pancreas and gallstones. The cystic component was hypointense on T1-weighted magnetic resonance images and hyperintense on T2-weighted magnetic resonance images. A laparoscopic distal pancreatectomy was performed with the presumptive diagnosis of a mucinous cystic neoplasm or an intraductal papillary mucinous neoplasm with gallstones. The pathological examination showed that the walls of the two cysts were covered with non-keratinized stratified squamous epithelium, surrounded by normal splenic tissue. The final pathological diagnosis was two epithelial cysts originating from an intrapancreatic accessory spleen. Conclusions Even though multiple masses were detected in the pancreatic tail, the possibility of epithelial cysts originating from an accessory spleen should be considered. Laparoscopic distal pancreatectomy might be a safe and effective procedure and provide good cosmetic result for a benign or low-grade malignant tumor in the pancreas.

INTRODUCTION

Accessory spleen is a congenital abnormality consisting of normal splenic tissue in ectopic sites that is found in approximately 10-15% of the general population. However, an intrapancreatic accessory spleen has seldom been reported and multiple epithelial cysts in the intrapancreatic accessory spleen are extremely rare. We herein report a case of 37-year-old woman with two epithelial cysts originating from an intrapancreatic accessory spleen who underwent laparoscopic distal pancreatectomy

CASE REPORT

An asymptomatic, 37-year-old woman was admitted to our hospital for surgery. In 2006, she was determined to have two cystic lesions in the pancreatic tail, 15 and 13 mm in size, respectively. By 2012, these cystic lesions had grown to 40 and 20 mm in size, respectively. She had a history of mixed connective tissue disease and took 2 mg of prednisone per day. Blood chemistry and urinalysis were within normal limits. The tumor markers CA 19-9 (251 U/mL; reference range 0-37 U/mL) and SPAN-1 (38 U/mL; reference range 0-30 U/mL) were increased. Computed tomography showed a multilocular cyst, 40 mm in size, and a unilocular cyst, 20 mm in size, in the tail of the pancreas and gallstones. The cystic component was hypointense on T1-weighted magnetic resonance images and hyperintense on T2-weighted magnetic resonance images (Figure 1). On magnetic resonance cholangiopancreatography, these cysts did not connect with the main pancreatic duct and had no solid components. Fluorine-¹⁸fluorodeoxyglucose positron emission tomography (FDG-PET) showed no significant increase in the maximum standard uptake value. Suspecting a mucinous cystic neoplasm or an intraductal papillary mucinous neoplasm with gallstones, a laparoscopic distal pancreatectomy was performed. First, the spleen and the pancreatic tail were mobilized from the retroperitoneum using the four-port technique laparoscopically (Figure 2). After the mobilization, the splenic artery was identified, double clipped, and ligated. The splenic vein was also clipped and dissected. After access was achieved through the 5 cm suprapubic incision, the pancreatic tail and spleen including the two cystic lesions were transected with a linear stapler (Endo GIA Ultra Universal Stapler, 30 mm Black, Covidien, Dublin, Ireland) (Figure 3) and extracted from the peritoneal cavity. A cholecystectomy was also performed. The operative time was 278 min and the blood loss was 50 mL.

Figure 1. Magnetic resonance imaging showed a multilocular cyst, 40 mm in size, and a unilocular cyst, 20 mm in size, in the tail of the pancreas.

Figure 2. The laparoscopic procedure was performed using the four-port technique. The resected spleen and pancreatic tail were pulled out through a 5 cm long suprapubic incision.

Figure 3. a. Laparoscopic view of the mobilization of the spleen and pancreatic tail. b. The pancreatic tail and spleen including the two cystic lesions have been transected with a linear stapler.

Macroscopically, the cut surface of the tumor showed a unilocular cyst and a multilocular cyst completely surrounded with a brown solid component that resembled normal spleen. A histopathological examination showed that the walls of the two cysts were composed of fibrous tissue. The inner surface of the cyst was partly covered with non-keratinized stratified squamous epithelium, surrounded by normal splenic tissue. The final pathological diagnosis was two epithelial cysts originating from an intrapancreatic accessory spleen (Figure 4). The patient had a pancreatic fistula (grade A, based on criteria of the International Study Group of Pancreatic Fistulas) and was managed conservatively. She was discharged on the 21^st postoperative day. After the operation, her serum CA 19-9 levels decreased to normal. Over 12 months of follow-up, she continued to do well.

Figure 4. a. Unilocular cyst in the intrapancreatic accessory spleen. b. Multilocular cyst in the intrapancreatic accessory spleen. c. The histological section shows that the fibrotic wall (F) lined with non-keratinized stratified squamous epithelium is surrounded by accessory spleen tissue (S) in the pancreatic parenchyma (P).

DISCUSSION

An accessory spleen is a congenital focus of healthy splenic tissue that is separated from the main body of the spleen. It results from failed fusion of the splenic anlage, which is located in the dorsal mesogastrium. This condition is observed in 10-30% of patients at autopsy. The splenic hilum is the most common site of an accessory spleen, followed by the pancreatic tail. In autopsy studies of 3,000 patients, 61 of 364 (17%) accessory spleens identified were found in the pancreatic tail [1]. Mortelé et al. performed abdominal CT scans in 1,000 consecutive patients. Of these patients, 156 (15.6%) had at least one accessory spleen, and intrapancreatic accessory spleens were seen in two patients (0.2%) [2].

However, cysts found within intrapancreatic accessory spleens are extremely rare. Nevertheless, a well-documented series of case reports can be found in the literature. Since the first case was described by Davidson et al [3] in 1980, 39 such cases, including the present report, have been documented in English language case reports (PubMed keywords: epithelial cyst, epidermoid cyst (epithelial inclusion cyst), intrapancreatic accessory spleen) [3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32] (Table 1). However, to the best of our knowledge, this report is the first to describe macroscopically multiple epithelial cysts within an accessory spleen.

Table 1. Reported cases of an epithelial cyst or an epidermal cyst arising in an intrapancreatic accessory spleen.
Case ID	Author, year	Age	Sex	Symptom	Size (cm)	Serum CA 19-9	Form of cyst	Preoperative diagnosis	Surgery
#1	Davidson, 1980	40	M	Nausea, vomiting, weight loss, anorexia	7.0	-	Multilocular	Pseudocyst, cystadenoma, cystadenocarcinoma	DP+S
#2	Hamada, 1981	51	M	Abdominal pain, vague	6.0	-	Unilocular	Pseudocyst	DP+S
#3	Nakae, 1991	37	F	Epigastric pain	6.5	-	Unilocular	Cystic mass	DP
#4	Morohoshi, 1991	32	F	Abdominal pain	6.0	Normal	Unilocular	Pancreatic tail cyst	CE
#5	Tang, 1994	38	M	Asymptomatic	2.3	-	Multilocular	Multiple cyst	DP+S
#6	Higaki, 1998	46	F	Left back pain	3.0	201	Multilocular	Pancreatic cyst	DP+S
#7	Furukawa, 1998	45	M	Asymptomatic	2.0	Normal	Multilocular	Malignant pancreatic tumor	DP
#8	Tateyama, 1998	67	F	Asymptomatic	3.0	Elevation	Multilocular	Malignant pancreatic tumor	DP+S
#9	Sasou, 1999	49	F	Asymptomatic	4.3	Normal	Multilocular	Cystic tumor	DP+S
#10	Choi, 2000	54	F	Epigastric pain, nausea, vomiting	15.0	-		Benign cystic tumor	DP+S
#11	Tsutsumi, 2000	51	M	Asymptomatic	2.5	Normal	Multilocular	Cystic tumor, accessory spleen	DP+S
#12	Horibe, 2001	48	M	Asymptomatic	2.0	53	Unilocular	Mucin-producing tumor	DP+S+N
#13	Fink, 2002	12	F	Asymptomatic	10	-	Multilocular	Infected abdominal cyst	DP
#14	Yokomizo, 2002	38	M	Asymptomatic	3.0	410	Multilocular	Mucinous cyst adenoma, adenocarcinoma, epidermoid cyst	DP+S
#15	Sonomura, 2002	45	F	Epigastric pain	3.5	159	Multilocular	Cystadenocarcinoma, solid cystic tumor	DP+S
#16	Kanazawa, 2004	58	F	Asymptomatic	2.5	62	Multilocular	Mucinous cystic tumor	DP
#17	Ru, 2007	41	M	Asymptomatic	2.5	-	Unilocular	Well-circumscribed pancreatic tumor	DP+S
#18	Servais, 2008	52	F	Asymptomatic	11.5	-	Multilocular	Malignant pancreatic tumor	DP+S
#19	Gleeson, 2008	32	F	Right upper quadrant abdominal pain	1.5	-	Unilocular	Cystic pancreatic neoplasm	DP+S
#20	Itano, 2008	40	M	Asymptomatic	4.0	Normal	Unilocular	Epidermoid cyst in intrapancreatic accessory spleen	DP+S
#21	Zhang, 2009	26	F	Asymptomatic	2.5	Normal	Unilocular	Cystic lesion in the tail of the pancreas	DP
#22	Itano, 2010	67	M	Epigastric pain, weight loss	1.5	182	Unilocular	Epidermoid cyst in intrapancreatic accessory spleen	LADP+S
#23 #24 #25	Kadota, 2010	57 70 37	F F M	Asymptomatic Asymptomatic Asymptomatic	6.0 1.8 10.0	Normal 48 647	Multilocular Unilocular Unilocular	Pancreatic cystic tumor Mucinous cystic tumor in the pancreas Serous cystic tumor, lymphoepithelial cyst	DP+S DP+S DP
#26	Horn, 2011	62	M	Vague, left sided abdominal pain	4.8	-	Unilocular	Retroperitoneal mass with a possible cystic component	CE
#27	Yamanishi, 2011	55	F	Asymptomatic	2.5	90	Unilocular	Mucinous cystic neoplasm	DP+S
#28	Iwasaki, 2011	36	F	Asymptomatic	3.4	79	Multilocular	Mucinous cystic neoplasm	LDP
#29	Urakami, 2011	50	F	Asymptomatic	3.0	-	Unilocular	Epidermoid cyst, cystic tumor of in an intrapancreatic accessory spleen	LADP
#30	Harris, 2012	39	M	Asymptomatic	2.5	Normal	Unilocular	Cystic pancreatic lesion possibly malignant	LADP+S
#31 #32 #33 #34 #35 #36 #37	Hu, 2012	25 43 59 34 26 50 66	M M M F F M M	Asymptomatic Asymptomatic Asymptomatic abdominal pain Asymptomatic Asymptomatic Abdominal discomfort	4.2 5.2 4.6 3.8 2.6 4.2 6.5	1 18 78 418 10 53 13	Unilocular Unilocular Multilocular Unilocular Unilocular Multilocular Unilocular	Cystic tumor Cystadenoma Cystic tumor Cystadenoma Cystadenoma Cystadenoma Cystic tumor	DP DP+S DP+S DP+S DP DP+S DP+S
#38	Hong, 2013	56	F	Anemia	4.0	Normal	Unilocular	Pancreatic cancer	SPDP
#39	Present case	37	F	Asymptomatic	4.0 2.0	251	Multilocular Unilocular	Mucinous cystic neoplasm Intraductal papillary mucinous neoplasm	LDP+S
CE: cyst excision; DP: distal pancreatectomy; F: female; LADP: laparoscopic-assisted distal pancreatectomy; LDP: laparoscopic distal pancreatectomy; PD: pancreaticoduodenectomy; M: male; N: nephrectomy; S: splenectomy; SPDP: spleen-preserving distal pancreatectomy

A review of previously reported cases reveals that these lesions can occur equally in men and women (18 men, 21 women) and occur most frequently in middle age, with a median age of 45 years (range: 12 to 70 years). All of the lesions were located in the tail of the pancreas. Over half of the presentations were asymptomatic (26 of 39), and several patients had various symptoms including abdominal pain, epigastric pain or discomfort (n=10), weight loss (n=2), nausea and vomiting (n=2), and so on. Serum CA 19-9 levels were elevated in 15 of 39 cases. The median maximum diameter of the cystic lesions was 3.65 cm (range: 1.5 to 11.5 cm). This entity can mimic a cystic neoplasm of the pancreas, and it is often difficult to diagnose preoperatively. Only 3 of 39 cases had a precise diagnosis of epithelial cyst arising in an intrapancreatic accessory spleen. The remaining diagnoses were as follows: cystic tumor (n=11); mucinous cystic neoplasm, including a mucin-producing pancreatic tumor (n=7); cystadenoma/cystadenocarcinoma (n=6); benign/malignant pancreatic tumor (n=5); pancreatic cyst (n=4); or pancreatic pseudocyst (n=2).

The serum CA 19-9 levels were elevated preoperatively but decreased postoperatively in the present case, as well as in previous cases [8, 27]. Although further studies are needed to clarify the mechanism that elevates serum CA 19-9 levels, some cases might show this elevation, and this should be taken into consideration in the differential diagnosis.

Distal pancreatectomy was performed under a preoperative diagnosis of pancreatic cystic neoplasms, possibly malignant tumors, in most cases. Only five cases were managed laparoscopically [24, 28, 29, 30, 32]. Laparoscopic technique has made significant strides and is thought to an effective method of surgical management in cases of pancreatic and splenic cystic lesions, avoiding the shortcomings of open surgery [33]. For unspecified tumors, such as the current case, that appear benign, even though malignancy cannot be completely ruled out, a laparoscopic procedure would therefore be one of the best ways to avoid the drawbacks of open surgery, such as considerable pain, a prolonged hospitalization, and a poor cosmetic result. In the current case, the patient was a young woman and she benefited from the good cosmetic result of laparoscopic surgery (Figure 5).

Figure 5. Postoperative scar at 3 months after surgery.

In conclusion, when an asymptomatic intrapancreatic mass is detected, even if multiple masses are present, the possibility of epithelial cysts originating from an accessory spleen should be considered. Laparoscopic distal pancreatectomy might be a safe and effective procedure and provide a good cosmetic result for benign or low-grade malignant cysts in the pancreas.

Received July 3^rd, 2013 – Accepted August 20^th, 2013

Key words Choristoma; Epidermal Cyst; Laparoscopy; Pancreatectomy; Spleen

Conflict of interest None of the authors have any conflicts of interest to declare

Correspondence
Masaki Wakasugi
Department of Surgery
Osaka Police Hospital
10-31 Kitayama-cho, Tennoujiku
Osaka 543-0035
Japan
Phone: +81-6.6775.6051
Fax: +81-6.6775.2838
E-mail: wakasugi@oph.gr.jp

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