eMedicine Specialties > Radiology > Gastrointestinal
Pancreas, Serous Cystadenoma
Updated: Dec 22, 2008
Introduction
Serous cystadenoma on a contrast-enhanced CT scan. Note the Swiss cheese–like enhancement and gentle external lobulation.
MRIs of serous cystadenoma. Top left, T1-weighted image; top right, T2-weighted image; bottom left, T1-weighted gadolinium-enhanced image; bottom right, fat-suppressed T1-weighted gadolinium-enhanced image. The mass is externally lobulated and hypointense on the T1-weighted image and hyperintense on the T2-weighted image, with septal enhancement and, atypically, some larger cysts. Image courtesy of Arnold C. Friedman, MD, FACR.
Sonogram of serous cystadenoma. The large mass in the head of the pancreas is externally lobulated, with some cystic-appearing regions, some solid-appearing regions, and increased through transmission. Image courtesy of Arnold C Friedman, MD, FACR.
Background
Cystic lesions of the pancreas are common, and 80-90% of these lesions are pseudocysts or retention cysts. Cystic neoplasms of the pancreas are less common, accounting for about 10-15% of all cystic pancreatic lesions. True cysts of the pancreas are rare. Pancreatic serous cystadenoma used to be referred to as microcystic cystadenoma or glycogen-rich cystadenoma. These terms are no longer considered appropriate. The preferred name is now serous cystadenoma.1,2
The two most common cystic neoplasms of the pancreas are serous cystadenoma and mucinous cystic neoplasms (formerly called macrocystic neoplasm, a term that is no longer appropriate). Serous cystadenoma is more common than mucinous cystic neoplasm, with a ratio of about 2:1. Intraductal papillary mucinous tumor (IPMT) is a more recently discovered cystic neoplasm that may be a variant of the mucinous cystic neoplasm. The important point to remember is that serous cystadenoma is benign, whereas the biologic behavior of mucinous cystic neoplasm and IPMT ranges from benign to malignant. Therefore, distinguishing these entities is of the utmost importance.
Related eMedicine topics:
Hepatic Cystadenomas
Biliary Cystadenoma/Cystadenocarcinoma
Pseudocyst, Pancreatic
Pathophysiology
Serous cystadenomas are fairly large at presentation, ranging from 4-20 cm, with an average size of 5-8 cm. Biliary obstruction is rare, and symptoms are generally nonspecific; they include nausea and abdominal pain. If the tumor is large enough, symptoms related to mass effects may predominate. Smaller tumors may be discovered incidentally on abdominal ultrasonography (US) or computed tomography (CT).
Frequency
United States
Pancreatic serous cystadenoma is classically rare. Over a 55-year period in a large population examined at the Mayo Clinic, only 40 patients underwent surgical treatment for this disease. However, as cross-sectional imaging has improved and become more widely used in aging populations, this tumor is now encountered as an incidental finding with greater frequency.
The incidence of this tumor is increased in patients with von Hippel-Lindau disease.
Mortality/Morbidity
Serous cystadenoma is a benign tumor. Most patients present with nonspecific symptoms such as abdominal pain, nausea, vomiting, or a palpable abdominal mass.
Sex
Serous cystadenoma is more common in women than in men. Most reported male-to-female prevalence ratios range from 1:2 to 1:3. Some reports state that as many as 66% of cases occur in women.
Age
The mean patient age at presentation is 62 years (range, 35-84 y).
Anatomy
Serous cystadenomas occur most commonly in the pancreatic head and body and rarely involve the main pancreatic duct. They are lined by a uniform layer of glycogen-secreting cuboidal cells.
Presentation
Signs and symptoms
Presenting symptoms are nonspecific. Most commonly, abdominal or back pain, nausea, or vomiting is present.
Serous cystadenoma is benign. About one quarter to one third of the patients have no symptoms, and most of the remaining patients present with a variety of nonspecific symptoms such as nausea, anorexia, weight loss, and abdominal pain. Symptoms related to biliary obstruction, other local mass effects, or pancreatitis are rare. The incidence of this tumor is increased in patients with von Hippel-Lindau disease.3
Diagnosis
The main differential diagnoses include the following: mucinous cystic neoplasm, IPMT, pseudocyst, focal pancreatitis, and adenocarcinoma.
The diagnosis of pancreatitis and pseudocyst is generally straightforward, especially in a clinical setting of chronic alcoholism with a history of pancreatitis.
Imaging findings are usually confirmatory in difficult cases. Adenocarcinoma is most commonly solid and, therefore, infrequently confused with cystic neoplasms. The other entities can have imaging features that are highly suggestive of one entity rather than another. Communication with the pancreatic duct strongly suggests mucinous cystic neoplasm or IPMT instead of serous cystadenoma.
A central stellate scar with calcification and a grapelike cluster of cysts and external lobulation strongly suggests serous cystadenoma. However, the imaging features of these entities can overlap considerably; therefore, an analysis of the percutaneous cells and cystic fluid is often required for diagnosis. In fact, approximately 10% of all serous cystadenomas have cystic components larger than 2 cm and cannot be distinguished from mucinous cystic neoplasms.
The following table presents the relative values for amylase, carcinoembryonic antigen (CEA), mucin, and viscosity, as well as the cytologic features that can be used to differentiate these entities.
Table. Features in the Differentiation of Pancreatic Cysts
Open table in new window
Table
| Pathologic Entity | Amylase Level | CEA Level | Viscosity | Mucin Finding | Cytologic Features |
| Serous cystadenoma | Low | Low | Low | Negative | Glycogen-rich cells |
| Mucinous cystic neoplasms | Low | High | High | Positive | Mucinous cells |
| Pseudocyst | High | Low | Low | Negative | Inflammatory cells |
| Pathologic Entity | Amylase Level | CEA Level | Viscosity | Mucin Finding | Cytologic Features |
| Serous cystadenoma | Low | Low | Low | Negative | Glycogen-rich cells |
| Mucinous cystic neoplasms | Low | High | High | Positive | Mucinous cells |
| Pseudocyst | High | Low | Low | Negative | Inflammatory cells |
Preferred Examination
Findings from plain radiography and upper GI series are nondiagnostic, except the finding of a classic sunburst central calcification, which is suggestive. Ultrasonography can be used to detect, and sometimes to characterize, the features of this tumor, especially when the classic features are present. In comparison, CT is superior in lesion depiction and characterization, and it is the preferred imaging modality in the initial workup of pancreatic lesions. However, the first test performed is usually ultrasonography, because the typical presenting symptom is abdominal pain and/or nausea.4
MRI can be a useful problem-solving adjunct in select cases. For example, when an evaluation of the ducts is needed, magnetic resonance cholangiopancreatography (MRCP) can be useful.
Limitations of Techniques
When stellate calcification or the classic CT features of central sunburst are present in a multilocular cystic mass in an older woman, some institutions accept this as a clearly benign finding. In one series, however, CT was useful in depicting the lesions, but it was not useful in differentiating benign and malignant tumors, serous and mucinous tumors, or pseudocysts and neoplasms.
Differential Diagnoses
Pancreas, Adenocarcinoma
Pancreas, Mucinous Cystic Neoplasm
Pancreatitis, Acute
Pancreatitis, Chronic
Pseudocyst, Pancreatic
Other Problems to Be Considered
Mucinous cystic neoplasm
Intraductal papillary mucinous tumor (IPMT)
Pseudocyst
Focal pancreatitis
Adenocarcinoma
More on Pancreas, Serous Cystadenoma |
 Overview: Pancreas, Serous Cystadenoma |
| Imaging: Pancreas, Serous Cystadenoma |
| Follow-up: Pancreas, Serous Cystadenoma |
| Multimedia: Pancreas, Serous Cystadenoma |
| References |
| Further Reading |
| Next Page » |
References
Colonna J, Plaza JA, Frankel WL, Yearsley M, Bloomston M, Marsh WL. Serous cystadenoma of the pancreas: clinical and pathological features in 33 patients. Pancreatology. 2008;8(2):135-41. [Medline].
Garcea G, Ong SL, Rajesh A, Neal CP, Pollard CA, Berry DP, et al. Cystic lesions of the pancreas. A diagnostic and management dilemma. Pancreatology. 2008;8(3):236-51. [Medline].
Gupta R, Dinda AK, Singh MK, Misra MC. Macrocystic serous cystadenocarcinoma of the pancreas: the first report of a new pattern of pancreatic carcinoma. J Clin Pathol. Mar 2008;61(3):396-8. [Medline].
Lewin M, Hoeffel C, Azizi L, Lacombe C, Monnier-Cholley L, Raynal M, et al. [Imaging of incidental cystic lesions of the pancreas]. J Radiol. Feb 2008;89(2):197-207. [Medline].
Starkov IuG, Solodinina EN, Shishin KV, Plotnikova LS. [Endoscopic ultrasonography in diagnosis of surgical treatment of pancreas]. Khirurgiia (Mosk). 2008;47-52. [Medline].
Box JC, Douglas HO. Management of cystic neoplasms of the pancreas. Am Surg. May 2000;66(5):495-501. [Medline].
Carlson SK, Johnson CD, Brandt KR. Pancreatic cystic neoplasms: the role and sensitivity of needle aspiration and biopsy. Abdom Imaging. Jul-Aug 1998;23(4):387-93. [Medline].
Compton CC. Serous cystic tumors of the pancreas. Semin Diagn Pathol. Feb 2000;17(1):43-55. [Medline].
Kume N, Suga K, Nishigauchi K. [Evaluation of pancreatic cancers using thallium-201 single photon emission computed tomography]. Nippon Igaku Hoshasen Gakkai Zasshi. Aug 1995;55(9):682-9. [Medline].
Lewandrowski KB, Southern JF, Pins MR. Cyst fluid analysis in the differential diagnosis of pancreatic cysts. A comparison of pseudocysts, serous cystadenomas, mucinous cystic neoplasms, and mucinous cystadenocarcinoma. Ann Surg. Jan 1993;217(1):41-7. [Medline].
Megibow AJ, Lavelle MT, Rofsky NM. MR imaging of the pancreas. Surg Clin North Am. Apr 2001;81(2):307-20, ix-x. [Medline].
Sarr MG, Kendrick ML, Nagorney DM. Cystic neoplasms of the pancreas: benign to malignant epithelial neoplasms. Surg Clin North Am. Jun 2001;81(3):497-509. [Medline].
Warshaw AL, Compton CC, Lewandrowski K. Cystic tumors of the pancreas. New clinical, radiologic, and pathologic observations in 67 patients. Ann Surg. Oct 1990;212(4):432-43; discussion 444-5. [Medline].
Further Reading
Related eMedicine topics:
Hepatic Cystadenomas
Biliary Cystadenoma/Cystadenocarcinoma
Pseudocyst, Pancreatic
Keywords
microcystic cystadenoma, glycogen-rich cystadenoma, benign cystic neoplasm of the pancreas
