From the Guidelines
The most important investigation for mucinous cystadenoma of the pancreas after fine needle aspiration (FNA) of the cyst fluid is carcinoembryonic antigen (CEA) level measurement in the aspirated fluid. This is based on the strongest and most recent evidence from the study published in the Journal of the American College of Radiology in 2020 1. The study suggests that a CEA threshold level in the range of 192 to 200 ng/mL is 80% accurate for the diagnosis of a mucinous cyst. Key points to consider in the investigation of mucinous cystadenoma after FNA include:
- CEA levels above 192 ng/mL strongly suggest a mucinous cystic lesion, helping to differentiate mucinous cystadenomas from other pancreatic cystic lesions such as serous cystadenomas or pseudocysts.
- Cytological examination of the fluid should be performed to look for mucin-producing epithelial cells and to rule out malignant cells, though cytology alone has limited sensitivity.
- Cyst fluid analysis should also include amylase levels, which are typically low in mucinous cystadenomas compared to pseudocysts.
- Molecular assays for markers such as K-ras, GNAS, PTEN, VHL, TP53, and PIK3CA may also assist in differentiating neoplastic cystic lesions and predicting cyst behavior. The European evidence-based guidelines on pancreatic cystic neoplasms published in Gut in 2018 also support the use of CEA level measurement in the diagnosis of mucinous cystadenoma 1. Additionally, the study published in Nature Reviews Gastroenterology and Hepatology in 2011 provides further evidence for the use of CEA level measurement in the diagnosis of mucinous cystadenoma, with a cutoff level of CEA >192 ng/ml proving to be capable of predicting the presence of a mucin-producing cyst with a sensitivity of 73% and a specificity of 65% 1. Overall, the measurement of CEA levels in the aspirated fluid is the most important investigation for mucinous cystadenoma of the pancreas after FNA, and it should be used in conjunction with other diagnostic tools to guide appropriate management decisions.
From the Research
Characteristic Investigation of Mucinous Cystadenoma of the Pancreas
The most important investigation for mucinous cystadenoma of the pancreas after Fine Needle Aspiration (FNA) of the cyst fluid is:
- High CEA in cyst fluid, as it is a significant marker for differentiating mucinous cystadenoma from other pancreatic cystic neoplasms 2, 3, 4, 5
Key Findings
- Elevated CEA levels (> or =480 ng/mL) accurately predict mucinous cystic neoplasms (MCN) from serous cystadenoma (SCyA) and pseudocysts (PC) 2
- CEA levels > or =6000 ng/mL can differentiate malignant from benign MCN 2
- Cyst fluid amylase levels are higher in pseudocysts compared to mucinous cystic neoplasms, but do not differentiate between MCN and intraductal papillary mucinous neoplasms (IPMN) 6
- The combination of cyst fluid CEA and amylase values may increase the diagnostic accuracy for differentiating mucinous neoplasms from pseudocysts 6
Diagnostic Markers
- CEA: a significant marker for mucinous cystadenoma, with elevated levels indicating a high likelihood of MCN 2, 3, 4, 5
- Amylase: higher levels in pseudocysts, but not diagnostic for MCN or IPMN 6
- Viscosity (VIS): lower in pseudocysts and serous cystadenoma, higher in mucinous cystadenoma and mucinous cystadenocarcinoma 2