Masaki Wakasugi1*, Masayuki Tori1, Hiroki Akamatsu1, Shigeyuki Ueshima1, Takeshi Omori1, Mitsuyoshi Tei1, Toru Masuzawa1, Masahiko Tsujimoto2 and Toshirou Nishida1
Departments of 1Surgery and 2Pathology, Osaka Police Hospital. Osaka, Japan
Received July 3rd, 2013 – Accepted August 20th, 2013
Context Accessory spleen is a congenital abnormality consisting of normal splenic tissue in ectopic sites that is found inapproximately 10-15% of the general population. However, an intrapancreatic accessory spleen has seldom been reportedand multiple epithelial cysts in the intrapancreatic accessory spleen are extremely rare. Case report A 37-year-old womanwith no clinical manifestations presented with two cystic lesions in the tail of the pancreas. The tumor markers CA 19-9 (251U/mL) and SPAN-1 (38 U/mL) were increased. Computed tomography showed a multilocular cyst, 40 mm in size, and aunilocular cyst, 20 mm in size, in the tail of the pancreas and gallstones. The cystic component was hypointense onT1-weighted magnetic resonance images and hyperintense on T2-weighted magnetic resonance images. A laparoscopicdistal pancreatectomy was performed with the presumptive diagnosis of a mucinous cystic neoplasm or an intraductalpapillary mucinous neoplasm with gallstones. The pathological examination showed that the walls of the two cysts werecovered with non-keratinized stratified squamous epithelium, surrounded by normal splenic tissue. The final pathologicaldiagnosis was two epithelial cysts originating from an intrapancreatic accessory spleen. Conclusions Even though multiplemasses were detected in the pancreatic tail, the possibility of epithelial cysts originating from an accessory spleen should beconsidered. Laparoscopic distal pancreatectomy might be a safe and effective procedure and provide good cosmetic resultfor a benign or low-grade malignant tumor in the pancreas.
Choristoma; Epidermal Cyst; Laparoscopy; Pancreatectomy; Spleen
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
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.
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 21st 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).
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 . 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%) .
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  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.
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 . 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).
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.
None of the authors have any conflicts of interest to declare