Serous cystadenoma of the pancreas, also referred as microcystic adenoma, is an uncommon type of benign cystic pancreatic neoplasm.
There is a recognized strong female predilection (M:F ~ 1:4) and usually presents in middle age to elderly patients (>60 years of age).
Most patients are asymptomatic 17. Some may present with pain, weight loss, jaundice, or a palpable mass 4,5.
Pancreatic serous cystadenomas are benign neoplasms composed of numerous small cysts that are arrayed in a honeycomb-like formation. There can be significant variation in locule size (1-20 mm) 2-4.
Most individual cysts are typically <10 mm 12.
Three morphological patterns have been described 1:
- polycystic: 70%
- honeycomb: 20%
- oligocystic (macrocystic variant): <10% (cysts can be larger than 20 mm)
The cysts are lined by glycogen-rich flat or cuboidal epithelium separated by fibrous septa that radiate from a central scar, which may be calcified. Lesions can be rather large at presentation (~5 cm).
- von Hippel Lindau (vHL) disease: can be multiple or diffuse and present at a younger age
Lesions are distributed throughout the pancreas. In the largest series, they were found in the head/uncinate process 40% of the time, body 34%, and tail 26% 17.
- nonspecific and will usually be normal
- may demonstrate amorphous central calcification overlying the pancreas
- nonspecific hypoechoic mass in the pancreatic head region, possibly with internal echoes indicating microcysts (the oligocystic subtype may demonstrate individually identifiable cysts 5)
- typically demonstrates a multicystic, lobulated mass in the pancreatic head sometimes described as a 'bunch of grapes'
- the individual cysts are typically <20 mm in size and greater than six in number (except for the oligocystic variety)
- a characteristic enhancing central scar may be present which can show associated stellate calcification (present in ~20% of cases)
Serous cystadenomas usually appear as a cluster of small cysts within the pancreas. There is no visible communication between the cysts and the pancreatic duct.
Signal characteristics include:
- T1: typically low signal
- T2: the central fibrous scar (if present) is of a low signal while cystic components themselves are of a high signal
- T1 C+ (Gd): fibrous septa between them may enhance on delayed contrast-enhanced images
- may show enhancement due to hypervascular components 4
Treatment and prognosis
Most lesions should be observed without treatment, unless there is diagnostic uncertainty or significant associated symptomatology 5,17. They are benign lesions and do not recur once resected 4.
General imaging differential considerations on cross-sectional imaging include:
- intraductal papillary mucinous tumor (IPMN) of the pancreas: communicates with pancreatic ducts
- pancreatic pseudocyst
mucinous cystic neoplasm of the pancreas (e.g. mucinous cystadenoma)
- calcification tends to be peripheral
- usually unilocular
- if multilocular type, individual cysts tend to be >20 mm in size
- solid pseudopapillary tumor with cystic changes and necrosis 16
- 1. Choi JY, Kim MJ, Lee JY et-al. Typical and atypical manifestations of serous cystadenoma of the pancreas: imaging findings with pathologic correlation. AJR Am J Roentgenol. 2009;193 (1): 136-42. doi:10.2214/AJR.08.1309 - Pubmed citation
- 2. Kim HJ, Lee DH, Ko YT et-al. CT of serous cystadenoma of the pancreas and mimicking masses. AJR Am J Roentgenol. 2008;190 (2): 406-12. doi:10.2214/AJR.07.2808 - Pubmed citation
- 3. Cohen-scali F, Vilgrain V, Brancatelli G et-al. Discrimination of unilocular macrocystic serous cystadenoma from pancreatic pseudocyst and mucinous cystadenoma with CT: initial observations. Radiology. 2003;228 (3): 727-33. doi:10.1148/radiol.2283020973 - Pubmed citation
- 4. Genevieve L. Bennett et.al, Radiologic-Pathologic Conferences of the Massachusetts General Hospital Serous Cystadenoma of the Pancreas , AJR 1993;161:786
- 5. Buck JL, Hayes WS. From the Archives of the AFIP. Microcystic adenoma of the pancreas. Radiographics. 1990;10 (2): 313-22. Radiographics (abstract) - Pubmed citation
- 6. Yeh HC, Stancato-pasik A, Shapiro RS. Microcystic features at US: a nonspecific sign for microcystic adenomas of the pancreas. Radiographics. 21 (6): 1455-61. Radiographics (full text) - Pubmed citation
- 7. Khurana B, Mortelé KJ, Glickman J et-al. Macrocystic serous adenoma of the pancreas: radiologic-pathologic correlation. AJR Am J Roentgenol. 2003;181 (1): 119-23. AJR Am J Roentgenol (full text) - Pubmed citation
- 8. Sahani DV, Kadavigere R, Saokar A et-al. Cystic pancreatic lesions: a simple imaging-based classification system for guiding management. Radiographics. 25 (6): 1471-84. doi:10.1148/rg.256045161 - Pubmed citation
- 9. Buetow PC, Rao P, Thompson LD. From the Archives of the AFIP. Mucinous cystic neoplasms of the pancreas: radiologic-pathologic correlation. Radiographics. 18 (2): 433-49. Radiographics (abstract) - Pubmed citation
- 10. Itai Y, Ohhashi K, Furui S et-al. Microcystic adenoma of the pancreas: spectrum of computed tomographic findings. J Comput Assist Tomogr. 12 (5): 797-803. - Pubmed citation
- 11. Dewhurst CE, Mortele KJ. Cystic tumors of the pancreas: imaging and management. Radiol. Clin. North Am. 2012;50 (3): 467-86. doi:10.1016/j.rcl.2012.03.001 - Pubmed citation
- 12. Kalb B, Sarmiento JM, Kooby DA et-al. MR imaging of cystic lesions of the pancreas. Radiographics. 2009;29 (6): 1749-65. Radiographics (full text) - doi:10.1148/rg.296095506 - Pubmed citation
- 13. Macari M, Megibow AJ. Focal cystic pancreatic lesions: variability in radiologists' recommendations for follow-up imaging. Radiology. 2011;259 (1): 20-3. doi:10.1148/radiol.11102437 - Pubmed citation
- 14. Iannicelli E, Carbonetti F, Di Pietropaolo M et-al. Magnetic resonance cholangiopancreatography with secretin stimulation in the diagnosis of intraductal papillary mucinous neoplasm: a paradigmatic case report. Case Rep Radiol. 2014;2014: 820359. doi:10.1155/2014/820359 - Free text at pubmed - Pubmed citation
- 15. Purysko AS, Gandhi NS, Walsh RM et-al. Does secretin stimulation add to magnetic resonance cholangiopancreatography in characterising pancreatic cystic lesions as side-branch intraductal papillary mucinous neoplasm?. Eur Radiol. 2014;24 (12): 3134-41. doi:10.1007/s00330-014-3355-y - Pubmed citation
- 16. Kim HJ, Lee DH, Ko YT,et al. CT of serous cystadenoma of the pancreas and mimicking masses. (2008) AJR. American journal of roentgenology. 190 (2): 406-12. doi:10.2214/AJR.07.2808 - Pubmed
- 17. Jais B, Rebours V, Malleo G, et al. Serous cystic neoplasm of the pancreas: a multinational study of 2622 patients under the auspices of the International Association of Pancreatology and European Pancreatic Club (European Study Group on Cystic Tumors of the Pancreas). (2016) Gut. 65 (2): 305-12. doi:10.1136/gutjnl-2015-309638 - Pubmed
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