Zhuo Zhang, Jian Cheng Wang
Department of Surgery, Rui Jin Hospital Medical College Jiao Tong University. Shanghai, PR China
Received: 29 May 2009 Accepted: 20 July 2009
Context Generally, ectopic splenic tissue such as an accessory spleen is reported to have an incidence of 10% in the general population. However, an intrapancreatic accessory spleen has seldom been reported and cyst formation of the intrapancreatic accessory spleen is extremely rare. Case report A 26-year-old female patient with no clinical manifestations presented with a cyst in the tail of the pancreas which had been diagnosed by ultrasonography. A spleen-preserving distal pancreatectomy was performed with the presumptive diagnosis of a mucinous cystic tumor originating from the pancreas. The intraoperative frozen section showed the possibility of serous cystadenoma of the pancreas. The pathological examination revealed the cyst to be stratified squamous epithelium and was surrounded by splenic tissue and the final diagnosis was epithelial splenic cyst in an intrapancreatic accessory spleen. Conclusion Although great progress has been made with modern imaging techniques, it is still difficult to make a definitive diagnosis of cystic lesions in the pancreas.
Epidermal Cyst; Pancreas; Spleen
An accessory spleen has an incidence of 10% in thegeneral population and 16-20% of accessory spleensare reported to be attached to the tail of the pancreas.The incidence of accessory spleens in the pancreas israre and cystic formation, which has often beenmisdiagnosed as a mucinous cystic tumor originatingfrom the pancreas, has seldom been reported. Weherein report the case of an epithelial cyst in anintrapancreatic accessory spleen.
A 26-year-old female patient with a cystic lesion in thetail of the pancreas was admitted for further evaluation.Clinically, the patient had no symptoms, such asepigastric discomfort, nausea, and dyspepsia or weightloss. She had no history of acute pancreatitis orabdominal trauma. Physical examination did not showany pathological findings. Bilirubin levels andtransaminases were within the normal range. Serumamylase, CA 1-99 and CEA were found to be normal inserum analysis.
Ultrasonography imaging demonstrated a cystic lesionin the tail of pancreas adjacent to the spleen. ContrastenhancedCT scans revealed a cystic lesion without aseptum (diameter 2.5 cm) in the tail of the pancreas (Figure 1); contrast-enhanced imaging of the cysticwall revealed a density similar to that of the pancreas.Endoscopic ultrasonography (EUS) imaging showedthe same findings as the CT scans and ultrasonography.EUS-guided FNA revealed some monostratum cubicalepithelium and the CEA of the aspirated fluid waswithin the normal serum level.
The patient underwent a spleen-preserving distalpancreatectomy with a presumptive diagnosis ofprimary mucinous cystic tumor of the pancreas. Duringthe operation, a lesion with a diameter of 2.5cm wasfound in the tail of the pancreas, closely attached to thespleen and was completely resected (Figure 2). Clearfluid was found in the cyst and an intraoperative frozensection suggested a diagnosis of serous cystadenoma ofthe pancreas. After the operation, the specimen wassent for histopathological examination. Macroscopically,the lesion had clear borders with the surroundingpancreatic tissue and a unilocular cyst measuring2.5x2.5 cm was found in its center. Microscopically,the inner surface of the cyst was lined with stratifiedsquamous epithelium without sebaceous or sweatglands. Normal splenic tissue including splenic redpulp, splenic white pulp and trabecula of the spleenwas found in the layer of the cystic wall. The exteriorof the cyst was composed of fibrous connective tissueand some tubular elements. Final diagnosis of the lesion was an epithelial splenic cyst in an intrapancreaticaccessory spleen (Figure 3).
Seventy-five percent of splenic cysts are post-traumaticpseudocysts; other cysts of the spleen can be classifiedinto parasitic and non-parasitic cysts [1, 2]. Cystformation of an accessory spleen in the tail of thepancreas is extremely rare and only few cases havebeen reported. Clinically, most patients with thisdisease have no clinical symptoms or signs and it isoften detected incidentally by imaging studies. Serumtumor markers, such as CEA, CA 19-9 and CA 125,have no role in diagnosing this disease [3, 4, 5]. Ahypervascular blush of the wall of the cyst, which hasthe same density on enhanced CT as that of the spleen,was said to be of help in diagnosing this abnormalitybut not in all cases  as was demonstrated in our case.Histologically, epithelial cysts are lined with stratifiedsquamous epithelium with no skin appendages, such assebaceous and sweat glands .
Until now, there have been no reports of malignancy ofepithelial splenic cysts of an intrapancreatic accessoryspleen. The patient can be followed up without anyfurther treatment if the cyst is small and has nosymptoms or signs. Since an epithelial splenic cyst inthe pancreas lacks particular characteristics on radiological examination, it is especially difficult todifferentiate it from a pancreatic mucinous cysticlesion. EUS and FNA, together with measurement ofCEA levels would provide diagnostic assistance sinceelevated CEA leads to a mucinous cyst while normalCEA does not. Most cases lacked a proper preoperative
diagnosis and therefore the suspicion of a mucinouscyst tumor mandated surgery [7, 8]. Finally, epithelialsplenic cysts should be considered in the differentialdiagnosis of a cystic lesion in the tail of the pancreas,and en-bloc resection of the cyst including normalpancreatic tissue should be performed withpreservation of the spleen when possible.
Conflict of interest The authors have no potentialconflicts of interest