We report the unusual occurrence of a patient with recurrent pancreatitis caused by the underlying presence of a benign mucinous cystadenoma of the distal pancreas. There are only two previous case reports of a mucinous cystadenoma causing acute pancreatitis[1,2] and two case reports of the coexistence of a pancreatic pseudocyst with a mucinous cystadenoma.[3,4]

 

Case Report

 

A 54-year old female was admitted for recurrent bouts of central abdominal pain radiating to back since last 6 months. Her past medical history was significant for hypertension, which was currently controlled. The admission laboratory tests showed normal liver function tests, normal white blood cell count, but her amylase and lipase were 216 U/L (normal range, 27-137 U/ L) and 2217 U/L (normal range, <190 U/L), respectively. She was treated for acute pancreatitis and was discharged 7 days later.

 

However, she returned six weeks after discharge with recurrent mid-epigastric pain with radiation to her back, nausea, and vomiting, and continued early satiety. Her laboratory tests again showed elevated amylase and lipase of 498U/L and 3025 U/L, respectively. Contrasted abdominal CT showed a 10 cm cystic mass in the midbody/tail of the pancreas with an anterior rim of normal appearing pancreas (Figure 1).

 

Endoscopic retrograde cholangiopancreatography (ERCP) revealed a normal caliber pancreatic duct with an abrupt cutoff at the distal duct. She underwent exploratory laparotomy. After gaining access to the lesser sac, a 10 cm cystic lesion was identified at the junction of the body and tail of the pancreas (Figure 2).

 

However, there were dense adhesions and inflammation surrounding the 10 cm cystic lesion at the junction of body and the tail of the pancreas. Enbloc distal pancreas and spleen was removed (Figure 3). The final pathology confirmed the presence of a mucinous cystadenoma with its characteristic features: a mucin-producing columnar epithelium lining the cyst wall, underlying ovarian-type stromal tissue, and no evidence of dysplasia. The patient had an uneventful recovery, began to tolerate oral intake, and was discharged 7 days after surgery.

Discussion

Mucinous cystadenomas are a benign type of mucinous cystic neoplasm of the pancreas (MCNs). Patients with mucinous cystadenomas have a mean presentation of 48 years with a distinct female predominance as high as 9:1 in some series.[5,6] These cystic tumors are typically large (50% are greater than 5 cm) and most (greater than 50%) are located in the distal body and tail of the pancreas. Patients most often present with nonspecific abdominal pain, nausea, vomiting, and weight loss.

In published series there are only two cases in the literature that attribute the development of acute pancreatitis to a mucinous cystadenoma.[1,2] Likewise, there are only two cases that describe the coexistence of a pseudocyst and a mucinous cystadenoma.[3,4] There are no reported cases of a mucinous cystadenoma causing recurrent pancreatitis. Rattner et al. found that in computed tomography neoplastic process is highly suggestive by presence of solid components in the wall of the cyst.[7] Most pseudocysts are single and have few solid components, septae or loculations, or calcifications in the cyst wall. Hsieh and colleagues reported that, magnetic resonance imaging easily differentiated a pseudocyst from a mucinous cystadenoma.[4] T1-weighted, T2-weighted, and gadolinium-enhanced images may delineate loculations, septae, and further define the surrounding tissue in order to differentiate the cystic lesions.

Endoscopic ultrasound is a diagnostic tool which provides morphologic detail, and sampling of fluid from the lesion for measurement of enzymes, viscosity, measurement of tumor markers, and cytologic examination. Song et al. observed that pseudocysts contained echogenic debris and demonstrated parenchymal changes more often than cystic neoplasm. In addition, internal septae were seen with EUS more frequently in cystic neoplasms.[8]

Cyst fluid may be used for diagnosis by cytology and measurement of various tumor markers. A high concentration of amylase in the cyst fluid is diagnostic of a pancreatic psuedocyst.[9] Similarly, a high carcinoembryonic antigen (CEA) is indicative of a mucinous cystadenoma and a CEA of greater than 400 is potentially predictive of malignancy.[10] Mucin and mucinous cells are characteristic of mucinous cystic neoplasm, glycogen-staining cells are seen in serous cystadenomas, and inflammatory cells and histiocytes are associated with seudocysts. Even pancreatic acinar cell carcinoma may present with features of pancreatitis.[11] Fine needle aspiration cytology provides tissue diagnosis in such cases. 

Cystic pancreatic tumors constitute for about 10-15% of pancreatic cysts and less than 1% of pancreatic neoplasms.[12] World Health Organization (WHO) classified cystic pancreatic neoplasms into three main categories, mucinous variety (45%), serous variety (16%), and intraductal papillary mucinous neoplasm (IPMNs) (32%).[13] Sahani DV et al. have suggested a classification scheme for pancreatic cysts that is based on the imaging morphologic features of the cyst into four subtypes: (a) unilocular cysts, (b) microcystic lesions, (c) macrocystic lesions and (d) cysts with a solid component. Multiple unilocular cysts are most often pseudocysts resulting from prior pancreatitis.[14] Other causes of multiple cysts include von Hippel–Lindau disease and rarely IPMN. In von Hippel–Lindau disease, the pancreas is otherwise healthy and cysts may also be present in the kidneys or liver.[15] The presence of ovarian-type stroma has now becoming an essential requirement for the diagnosis of MCN, and when defined as such, MCN is seen almost exclusively in women of perimenopausal age group as thick-walled multilocular cystic mass in the tail of the pancreas.[16]

 

Benign and malignant cystic neoplasms are simply differentiated based on pathology. Any cystic neoplasm exhibiting invasive components is considered a malignant cystadenocarcinoma. For patients with benign serous or mucinous cystadenomas, complete resection is curative. Patients with resected mucinous cystadenocarcinomas typically live much longer than those with resected ductal adenocarcinoma, with an approximate 50 percent 5-year survival.[17]

 

References

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