Jason - Cystic Lesion of the Pancreas: Case Presentation

A Young Woman With a Cystic Lesion of the Pancreas: Case Presentation
Case Presentation

A 41-year-old woman was referred for an abnormal gastroscopy. The patient had a history of gastroesophageal reflux disease. She had undergone upper endoscopy 1 week previously, and, at that time, was found to have extrinsic compression of the stomach. The patient has had no abdominal pain, nausea, vomiting, fever, chills, changes in bowel habits, or weight loss. She was referred to clinic for further evaluation.

Results of physical examination were unremarkable. Laboratory investigations showed normal hematology and chemistries, including serum amylase, lipase, and tumor markers.

Upper gastrointestinal endoscopy showed an extrinsic compression of the posterior wall of the gastric body (Figure 1). Computed tomography (CT) scan of the abdomen showed a 3-cm cystic lesion in the pancreas near the junction of the head and body (Figure 2). There was no other evidence of mass, adenopathy, or parenchymal pancreatic disease. The pancreatic and biliary ducts were normal. Intravenous contrast did not demonstrate any additional abnormality.

1. Is my cystic lesion neoplastic (15%) or nonneoplastic (no malignant potential 80% of all cysts) ? 
   - May be a Yes, because neoplastic cyst has 4 types: IPMN or IPMT (t for tumor) is one of them
2. Why is Jason's different from this lady's?
   - Age,
   - location is in the uncinated process (head and neck area),
   - communicate with ductal system
3. How do I know Jason's is IPMN or IPMT? or MDE?
   - MRI shows that the cyst is Multiloculated;
   -MRI indicates that both the main and the branch ducts are dilated.
   - communicates with ductal system

My symptoms

Recurrent, acute abdominal pain intermittently occured since a pancreatitis attach in 2002, for which I was hospitalized for a week at Huntington Methodist Memorial Hospital. Each time it started with sharp, cramping abdominal pain, followed with water like diarrhea; sometimes with vomiting. It subsided generally within 1 hour without any medication; I could go back to work the next day without feel anything.

I called 911 about once twice a year for this illness; and my wife took me to the emergency room for about one or two times a year. On average, it happened two to three times every year druing the last 9 years. The hospitals that I went are the Garfield Hospital, Monterey Park Hospital and Huntington Methodist Memorial Hospital


Management and Diagnostic Questions

What is your differential diagnosis of this patient's cystic lesion?

Most (70% to 80%) cystic lesions of the pancreas are nonneoplastic and have no malignant potential. These lesions are either pseudocysts complicating acute or chronic pancreatitis, or, rarely, true cysts. However, up to 15% of cystic lesions are neoplastic, with a variable propensity for malignancy. These cystic neoplasms are frequently misdiagnosed as pseudocysts, with potentially disastrous results.

Warshaw and colleagues[1] described cystic neoplasms of the pancreas in 67 patients seen between 1978 and 1989. Most of these lesions occurred in middle-aged women who presented with few symptoms. The average size of each lesion was 5 cm to 6 cm, and about 40% had been misdiagnosed as pseudocysts. Table 1 shows a simple classification scheme for cystic neoplasms of the pancreas. The 4 types most frequently encountered are:

1. mucinous cystic neoplasm (cancerous and noncancous),
2. serous cystadenoma,
3. papillary cystic neoplasm, and
4. intraductal papillary mucinous tumor.

Our patient has a relatively small lesion, which, on CT scan, has almost no solid component. She is young and may have a rare congenital cyst. Although, statistically, a pseudocyst is the most likely scenario, the absence of features suggestive of pancreatitis makes such a diagnosis less appealing. This patient may have a cystic neoplasm. Does accurate diagnosis make a difference in management?

How does definitive diagnosis affect management and outcome?

The mucinous cystic tumors (including mucinous cystic neoplasm, papillary cystic neoplasm, and intraductal papillary mucinous tumor) are all characterized by columnar epithelium lining the cystic spaces. These tumors may have frank malignancy at the time of diagnosis; all have malignant potential. These lesions must be resected. Serous cystadenomas have simple cuboidal cells lining the cysts and are generally not considered at risk for malignant progression. Pseudocysts and true cysts rarely need resection.

Although identification of a cystic lesion is relatively easy, the identification of a specific tumor type may be difficult. Clinical characteristics, such as sex of patient, size of cyst, location in the pancreas, and presence or absence of pain, do not help distinguish tissue types.[1]

What diagnostic modalities would provide a definitive diagnosis?

Specifically, what role do endoscopic ultrasound (EUS) and cyst aspiration play in the evaluation and management of cystic lesions of the pancreas? Abdominal ultrasound, CT, and magnetic resonance imaging may be used to differentiate between large (> 3 cm) cystic neoplasms and pseudocysts. Features that suggest a cystic neoplasm include multilocularity; thick, irregular walls and septae; and calcifications in the mass but not in the ducts. If a simple cyst communicates ( multilocularity <-> communication? - Jason )with the pancreatic duct on endoscopic retrograde cholangiopancreatography (ERCP), then a pseudocyst is suspected. However, these imaging techniques have not been adequately evaluated in assessing small lesions such as that seen in our patient. Table 2 shows that EUS and cyst aspiration may have a role in obtaining a definitive diagnosis for patients with cystic lesions of uncertain etiology.

EUS is useful for imaging the echo-architecture of a cystic mass in the pancreas and in predicting the probability of a cystic neoplasm.[2-5] Koito and coworkers[2] retrospectively evaluated the diagnostic accuracy of EUS in differentiating solitary pancreatic cystic tumors by comparing EUS diagnosis with histologic results in 52 resected specimens. In this study, the cut surfaces of the specimens were classified into 6 patterns (Figure 3). All nonneoplastic cysts were found to be either thin, septal type, or simple type; all neoplastic cysts belonged to the thick wall, tumor protruding, thick septal, or microcystic type. These investigators showed that EUS was able to accurately describe the internal architecture of pancreatic cystic tumors.

Hammel and associates[3] conducted a study to assess the diagnostic reliability of preoperative biochemical and tumor marker analysis in cyst fluid obtained by CT-guided fine-needle aspiration. Levels of serum amylase (upper limit of normal = 70 U/mL) and tumoral markers, including carcinoembryonic antigen (CEA; upper limits of normal = 5 ng/mL) and carbohydrate antigen 19.9 (CA 19-9; upper limit of normal = 37 U/mL), were measured in cyst fluid obtained preoperatively. The diagnosis of cystic neoplasms (7 serous cystadenomas and 12 mucinous tumors) was established by surgical specimen analysis. High CA 19-9 levels (> 50,000 U/mL) were indicative of mucinous tumors (75% sensitivity and 90% specificity). Low CEA levels (< 5 ng/mL) were indicative of serous cystadenomas (100% sensitivity and 86% specificity). High amylase levels (> 5000 U/mL) were indicative of pseudocysts (94% sensitivity and a 74% specificity).

Is surgery inevitable?

If there remains any diagnostic uncertainty after complete evaluation, all cystic lesions of the pancreas should be resected. Thus, unless there exists a set of diagnostic results that would virtually eliminate the possibility of a neoplasm with malignant potential, surgery should be done with the minimal evaluation.

In the case of the patient presented here, the physicians believed that EUS plus EUS-directed aspiration had the potential to provide sufficient information to allow surgery to be avoided. However, the patient was also presented with the alternative option of early operation. The patient elected to have the detailed evaluation.

Clinical Course and Outcome

The patient underwent EUS. Figure 4 shows the radial echo-image of the normal body of the pancreas and pancreatic duct. Figure 5 shows the radial echo-image of the cyst, which appears thin walled and has a thin septum (arrow).
Linear echo-endoscopy easily visualized the cyst (Figure 6) and was used to aspirate the cyst after the Doppler showed no blood flow (Figure 7). The fluid obtained by aspiration underwent cytologic examination and Figure 8 shows a low-power view of this cytology specimen.

Two types of cells are seen. The large, flat, pink epithelial cells were likely introduced into the specimen while sampling and the smaller blue cells are normal pancreatic duct cells. The specimen is not hypercellular and, therefore, is not likely to be from a neoplasm. Figures 9 and 10 are low- and high-powered views of the pancreatic ductal cells, respectively. There is no evidence of dysplastic or malignant cells.
Biochemical analysis of the cyst fluid revealed the following values: serum amylase > 100,000 U/mL; CEA = 2.2 ng/mL; CA 19-9 = 23 U/mL.

Taken together, the clinical information obtained from our patient, along with data presented in Table 2, suggest that our patient has a nonneoplastic cyst. By EUS, the cyst was either the simple type or thin-septal type, making neoplasia unlikely. By cytology, there was no evidence of neoplasia or malignancy. By biochemistry, mucinous tumor was unlikely and pseudocyst likely. The patient will have a repeat CT scan in 6 months.

Discussion

The case presented here helps us review some of the general principles regarding the diagnosis and management of cystic lesions of the pancreas.

It is important to distinguish a neoplastic cyst from a nonneoplastic cyst. Mucinous cystic tumors of the pancreas, including cystadenoma, cystadenocarcinoma, papillary cystic neoplasm, and mucinous ductal ectasia, have high malignant potential and should be resected.[6] Serous cystadenoma has a low malignant potential, as do true cysts and pseudocysts. EUS is useful for imaging the echo-architecture of a cystic mass in the pancreas and in predicting the probability of a cystic neoplasm. Cysts that are well defined, simple, uniloculated (single room - jason), or with thin septation are likely to be due to a nonneoplastic process. By contrast, complex cystic lesions with thick walls, thick septations, microcystic changes, or a solid lesion protruding into the cyst are more likely to be due to cystic pancreatic neoplasm.

Combined with clinical, radiologic, and echo-endoscopic data, cystic fluid analysis for amylase, CEA, and CA 19-9 levels may help provide an accurate diagnosis of cystic lesions of the pancreas. If there is any doubt regarding the nature of the lesion, surgical resection should be done.