Pancreatic Cyst

Pancreatic Cyst: Diagnostic Approach

A 63-year old woman was admitted because of a non symptomatic pancreatic cyst of 7.0 x 8.0 cm diagnosed by an abdominal ultrasound. She had a past history of breast cancer treated by surgery, radiotherapy and chemotherapy one year before. Physical examination was normal. Blood tests including tumor markers as carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (Ca 19-9) and the carbohydrate antigen 15-3 (Ca 15-3) were normal.

After a CT-scan, an Endoscopy Ultrasound with a fine needle aspiration (FNA-EUS) was indicated as a diagnostic approach. EUS-FNA was performed under anesthesia, with antibiotic prophylaxis, using an ultrasound needle EZ-Shot (NA-200H-8022B, Olympus)

The liquid analysis showed tumor markers elevated as follows:
CEA 359,8 ng/ml (N= 0 - 4,60),
Ca19-9 474,9 U/ml (N= 0 - 37),
Ca72-4 580,1 U/ml (N= 0 - 7).
Amylase 176 U/l (N= <120),
Lipase 150 (N= <120),
LDH 333 (N= <200)

The final diagnostic of Mucinous Cyst Adenoma was done.

Discussion:
Pancreatic cysts are found in 25% of patients that are evaluated during radiologic examinations. Diferential diagnosis includes basically pseudocysts, serous adenomas, mucinous adenomas and cystoadenocarcinomas. Although very rare, in our patient the possibility of a pancreatic pseudocyst secondary to asymptomatic pancreatitis post chemotherapy existed.
At endoscopy ultrasound (EUS) the pancreatic cystic lesions have certain morphologic characteristics that help to clarify their origin (mucinous or not). Mucinous lesions are bigger in size and usually present a septum or wall inside of the cyst. However, sometimes these characteristics are not enough and EUS-FNA with cystic liquid analyses becomes necessary.
Liquid analysis with a Ca 72-4 level >40 U/ml has a 63% sensitivity and 98% specificity for distinguishing mucinous cystadenomas and cystadenocarcinomas from serous cystadenomas and pseudocysts. A CEA level >400 ng/ml has a 57% sensitivity and a 100% specificity for distinguishing mucinous tumours and cystadenocarcinomas from pseudocysts. A CEA level <4 ng/ml had a 100% sensitivity and a 93% specificity for distinguishing serous cystadenomas from mucinous cystadenomas, cystadenocarcinomas and pseudocysts.
Finally, FNA-EUS with a combined measurement of CA 72-4 and CEA may be used to distinguish accurately mucinous cystadenomas and cystadenocarcinomas from serous cystadenomas and pseudocysts.

References:
1. Hammel P, et al. Diagnostic value of CA 72-4 and carcinoembryonic antigen determination in the fluid of pancreatic cystic lesions. Eur J Gastroenterol Hepatol. 1998 Apr; 10 (4):345-8.
2. Hammel P, et al. Preoperative cyst fluid analysis is useful for the differential diagnosis of cystic lesions of the pancreas. Gastroenterology. 1995 Apr; 108 (4):1230-5.