We report an unusual occurrence of a recurrent pancreatic pseudocyst caused by an underlying mucinous cystadenoma of the distal pancreas. A 54-year old female was admitted for acute pancreatitis. Her only risk factors included the use of hydrochlorothiazide and two or three glasses of wine daily. Abdominal computed tomography (CT) done a week after onset of her symptoms showed a 5-cm cystic lesion in the tail of the pancreas suspected to be a pseudocyst. Her symptoms subsequently resolved. One month later, she had another episode of pancreatitis and an abdominal CT showed an 11 16 cm pseudocyst along with the previously mentioned cystic lesion. Approximately 6 weeks after her initial presentation, she was taken to the operating room for an exploratory laparotomy and cyst gastrostomy for a symptomatic pseudocyst. An intraoperative frozen section of the cyst wall showed a fibrous wall with acute and chronic inflammation without an epithelial lining. Six weeks after her cyst gastrostomy, she returned with abdominal pain, early satiety, and anorexia. Abdominal CT showed reaccumulation of fluid within the pseudocyst and endoscopie retrograde cholangiopancreatography (ERCP) revealed a normal caliber pancreatic duct with an abrupt cutoff at the distal duct. She underwent exploratory laparotomy with drainage of 3 L of fluid from the pancreatic pseudocyst. After gaining access to the lesser sac, a 6-cm cystic lesion was identified in the tail of the pancreas. She underwent a distal pancreatectomy and splenectomy. The intraoperative and final pathology confirmed the presence of a benign mucinous cystadenoma. The patient had an uneventful recovery, began to tolerate oral intake, and was discharged 7 days after surgery. The differentiation between a pancreatic pseudocyst and benign cystic neoplasms of the pancreas is crucial to determine treatment options. Cystic neoplasms of the pancreas, whether mucinous or serous, have the potential to harbor malignancy, and resection is recommended.
THE CLINICAL DIFFERENTIATION BETWEEN benign cystic neoplasms of the pancreas and pancreatic pseudocysts can be difficult, but this is important because the treatment of these entities is quite different. Pancreatic pseudocysts are localized collections of pancreatic secretions in a cystic structure that lack an epithelial lining and occur as a result of surrounding tissues walling off a contained pancreatic duct disruption. The management of pseudocysts depends on the clinical setting, but they can often be managed non- operatively. Cystic neoplasms of the pancreas, whether mucinous or serous, have the potential to harbor malignancy, and resection is recommended for low-risk patients. Different imaging modalities, including computed tomography (CT), magnetic resonance imaging (MRI), and endoscopie ultrasound (EUS), can be employed to further differentiate these pancreatic lesions and guide decisions for clinical management.
We report the unusual occurrence of a patient with recurrent pancreatitis and a pancreatic pseudocyst caused by the underlying presence of a benign mucinous cystadenoma of the distal pancreas. There is one previous case report of a mucinous cystadenoma causing acute pancreatitis1 and another case report of the coexistence of a pseudocyst with a mucinous cystadenoma.2 We present the first case report of a mucinous cystadenoma of the pancreas associated with acute pancreatitis and concurrent pancreatic pseudocyst.
Case Report
A 54-year-old white female was admitted for acute pancreatitis after a 3-week history of midepigastric pain, nausea, early satiety, and episodic diarrhea. Her past medical history was significant for benign hypertension, which was currently controlled with hydrochlorothiazide, and she had undergone a laparoscopic cholecystectomy and hysterectomy in the past. She did report drinking two to three glasses of wine per night for approximately 5 years. The admission laboratory tests showed normal liver function tests, normal white blood cell count, but her amylase and lipase were 243 U/L (normal range, 27-137 U/L) and 2447 U/L (normal range,
However, she returned 3 days after discharge with recurrent midepigastric pain, nausea, and vomiting, and continued early satiety. Contrasted abdominal CT showed a 4-5 cm cystic mass in the midbody/tail of the pancreas with an anterior rim of normal appearing pancreas (Fig. 1). Approximately 1 week later, she was referred to our institution with her outside CT scans and was asymptomatic. At this point, it was believed that she had an acute pancreatic pseudocyst; however, a cystic neoplasm of the pancreas was still in our differential diagnosis. It was recommended that she return in 6 weeks for a follow-up CT scan, abstain from alcohol, discontinue her diuretic use, and eat a low-fat diet.
One month after her last admission, she returned to the emergency room with a 1 -week history of increasing midepigastric pain with radiation to her back and worsening of her early satiety. Her laboratory tests in the emergency room again showed elevated amylase and lipase of 598 U/L and 3036 U/L, respectively. Contrasted CT of the abdomen and pelvis showed the aforementioned 4-5 cm cystic lesion in the midbody/tail of the pancreas, but there was interval development of an additional larger cystic lesion measuring 11 16 cm at its largest diameter. This larger cystic lesion occupied the majority of the anterior abdomen, displacing the stomach, colon, and small bowel, and extended into the pelvis. There was significant compression of the body and tail of the pancreas adjacent to these cysts, but otherwise the pancreas appeared normal without ductal dilatation (Figs. 2, 3, and 4). The working diagnosis was a complex pseudocyst, but the original lesion was still distinctly seen.
FIG. 1. CT scan of the abdomen showing a 4-5 cm cystic mass in the body/tail of the pancreas.
FIG. 2. CT scan of the abdomen showing the previously seen cystic mass (Fig. 1) in the pancreas and interval development of additional large cystic lesions.
She returned to our institution with continued symptoms from this enlarging cystic lesion and was eager for operative intervention. Approximately 6 weeks after her initial presentation, she underwent an exploratory laparotomy and cyst gastrostomy draining 1.8 L of fluid from her pancreatic pseudocyst. An intraoperative frozen section of the cyst wall showed a fibrous wall with acute and chronic inflammation without an epithelial lining (Fig. 5) compatible with a pseudocyst. She was discharged from the hospital 3 days later.
One month after her cyst gastrostomy, she returned to the emergency room with a 2-week history of intermittent nausea, recurrent early satiety, and increasing abdominal distention. The day of presentation she experienced an acute onset of severe midepigstric pain with nausea and inability to tolerate oral intake. In the emergency room, her vital signs were normal, her laboratory values were normal, with the exception of an amylase and lipase of 428 U/L and 794 U/L, respectively. Her physical exam was significant for tenderness to palpation in the midepigastric area with obvious abdominal distention. Contrasted CT scan of the abdomen and pelvis showed reaccumulation of fluid within the pseudocyst cavity (Figs. 6, 7, and 8). Endoscopie retrograde cholangiopancreatography (ERCP) revealed a normal caliber common bile duct, normal common hepatic ducts with a normal intrahepatic biliary tree, and a normal cystic duct stump (Fig. 9). The pancreatogram showed a normal caliber main pancreatic duct out to the junction of the body and tail. However at this level, there was an abrupt cutoff suggestive of a high-grade stricture (Figs. 10 and 11). There was no evidence of communication between the main pancreatic duct and the patient’s psuedocyst.
With evidence of a high-grade distal pancreatic ductal stricture and possible distal ductal disruption, we decided to perform an exploratory laparotomy, distal pancreatectomy, and splenectomy. At surgery, 3 L of fluid were drained from the pancreatic pseudocyst, which occupied most of the abdominal cavity. Intraoperative frozen section of the cyst wall was consistent with a pancreatic pseudocyst. After access to the lesser sac was obtained through a small cystotomy, the head and body of the pancreas appeared normal. However, there were dense adhesions and inflammation surrounding a 6- cm cystic lesion in the tail of the pancreas. After removal of the distal pancreas and spleen, intraoperative frozen sections of the cystic lesion in the tail were consitent with a mucinous cystadenoma. 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 (Fig. 12). The patient had an uneventful recovery, began to tolerate oral intake, and was discharged 7 days after surgery.
FIG. 3. CT scan of the abdomen showing the previously seen cystic mass (Fig. 1) in the pancreas and interval development of additional large cystic lesions.
FIG. 4. CT sc\an of the abdomen showing the previously seen cystic mass (Fig. 1) in the pancreas and interval development of additional large cystic lesions.
FIG. 5. Histologic features of a pancreatic pseudocyst: fibrous wall with acute and chronic inflammation without an epithelial lining.
FIG. 6. CT scan of the abdomen 1 month after a cyst gastrostomy demonstrating reaccumulation of fluid within the pseudocyst cavity.
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.3-4 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, very few patients with mucinous cystadenomas present with acute pancreatitis nor are they complicated by the development of a pancreatic pseudocyst.3-4 There is only one case in the literature that attributes the development of acute pancreatitis to a mucinous cystadenoma.1 Likewise, there is only one case that describes the coexistence of a pseudocyst and a mucinous cystadenoma.2 There are no reported cases of a mucinous cystadenoma causing pancreatitis and recurrent pancreatic pseudocysts.
FIG. 7. CT scan of the abdomen 1 month after a cyst gastrostomy demonstrating reaccumulation of fluid within the pseudocyst cavity.
FIG. 8. CT scan of the abdomen 1 month after a cyst gastrostomy demonstrating reaccumulation of fluid within the pseudocyst cavity.
FIG. 9. ERCP showing a normal biliary ductal system and a cystic duct stump.
FIG. 10. Pancreatogram revealing a high-grade stricture of the pancreatic duct at the junction of the body/tail.
Many imaging modalities can be useful for differentiating between pancreatic pseudocysts and mucinous cystadenomas. Abdominal computeed tomography is now one of the most commonly used diagnostic tools for the differentiation between pseudocysts and cystic tumors. Rattner et al. suggested that computed tomography showing solid components in the wall of the cyst is highly suggestive of a neoplastic process.5 Most pseudocysts are single and have few solid components, septae or loculations, or calcifications in the cyst wall. In our case, the two cystic lesions had none of these differentiating features to aid our diagnosis. In a previously reported case, magnetic resonance imaging easily differentiated a pseudocyst from a mucinous cystadenoma.2 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 can also play a role in further characterizing cystic pancreatic lesions by providing additional morphologic detail, but it can also allow for sampling of fluid from the lesion for measurement of enzymes, viscosity, measurement of tumor markers, and cytologie examination. The literature is controversial with respect to the ability of EUS to differentiate cystic lesions of the pancreas. In a prospective study by Song et al., they concluded that EUS-determined imaging criteria were useful in delineating pancreatic pseudocysts from cystic neoplasms. In their experience, 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.6 However, Ahmad et al. also evaluated the utility of EUS in differentiating benign from malignant cystic lesions of the pancreas. They concluded that endosonographic features alone were not reliable in differentiating these lesions.7
FIG. 11. Pancreatogram revealing a high-grade stricture of the pancreatic duct at the junction of the body/tail.
Cytologic analysis and evaluation of various tumor markers within cyst fluid may be used for cyst diagnosis. 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 pseudocysts. A high concentration of amylase in the cyst fluid is diagnostic of a pancreatic psuedocyst. Similarly, a high carcinoembryonic antigen (CEA) is indicative of a mucinous cystadenoma and a CEA of greater than 400 is potentially predictive of malignancy.8
The importance of distinguishing cystic neoplasms (benign and malignant) from pseudocysts is essential to treatment of these entities. Pseudocysts may be managed multiple ways depending on symptomatology, size, and location. Nonoperative management and surveillance is appropriate in patients who are not symptomatic from their lesion. Pseudocysts that persist, cause symptoms, or become infected need to be addressed by an operative or nonoperative approach. Nonoperative drainage can be performed percuteaneously or endoscopically. Operative therapy provides internal drainage via a cystojejunostomy, cystogastrostomy, or a cystoduodenostomy, depending on the location and characteristics of the lesion. Because serous cystic neoplasms are virtually always benign, resection should probably be reserved for those patients who are symptomatic and when differentiation from a mucinous neoplasm cannot be made confidently. In contrast to serous cystic neoplasms, mucinous cystic neoplasms should be considered premalignant and be resected.
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 per cent 5- year survival.9
In conclusion, the current case illustrates the difficulty, yet the importance, in definitively distinguishing pancreatic psuedocysts from cystic neoplasms of the pancreas. There are multiple strategies in the management of pancreatic pseudocysts, both operative and nonoperative, but these would be inappropriate for cystic pancreatic neoplasms, benign and malignant. Imaging modalities, cyst fluid analysis, and cytologic fluid analysis help distinguish cystic lesions of the pancreas.
FIG. 12. Histologic features of a mucinous cystadenoma: mucin- producing columnar epithelium lining the cyst wall with underlying ovarian-type stromal tissue.
REFERENCES
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2. Hsieh CH, Tseng JH, Huang SF. Co-existence of a huge pseudocyst and mutinous cystadenoma: report of a case and the value of magnetic resonance imaging for differential diagnosis. Eur J Gastroenterol Hepatol 2002;14:191-4.
3. Sarr MG, Carpenter HA, Prabhakar LP, et al. Clinical and pathologic correlation of 84 mutinous cystic neoplasms of the pancreas-can one reliably differentiate benign from malignant (or or premalignant) neoplasms? Ann Surg 2000;231:205-12.
4. Warshaw AL, Compton CC, Lewandrowski K, et al. Cystic tumors of the pancreas: New clinical, radiologie, and pathologic observations in 67 patients. Ann Surg 1990;212:432-45.
5. Rattner DW, Castillo CF, Warshaw AL. Cystic pancreatic neoplasms. Ann Oncol 1999;10(suppl 4):s107-10.
6. Song MH, Lee SS, Park JS, et al. The role of endoscopic ultrasonography in pancreatic cystic lesions. Gastrointes Endosc 2002;55:AB249.
7. Ahmad NA, Kochman ML, Lewis JD, Ginsberg GC. Can EUS alone differentiate between malignant and benign cystic lesions in the pancreas? Am J Gastroenterol 2001;96:295-300.
8. Fernandez C, Warshaw AL. Cystic neoplasms of the pancreas. Pancreatol 2001;1:641-7.
9. Wilentz RE, Albores-Saavedra J, Zahurak N, et al. Pathologic examination accurately predicts prognosis in mutinous cystic neoplasms of the pancreas. Am J Surg Pathol 1999;23:1320-7.
ROBERT T. RUSSELL, M.D., KENNETH W. SHARP, M.D.
From Vanderbilt University Medical Center, Nashville, Tenneesee
Presented at the Annual Scientific Meeting and Postgraduate Course Program, Southeastern Surgical Congress, New Orleans, LA, February 11-15, 2005.
Address correspondence and reprint requests to Kenneth W. Sharp, M.D., Vanderbilt University Medical Center, Room D, 5203 Medical Center North, Nashville, TN 37232-2577.
Copyright The Southeastern Surgical Congress Apr 2005
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