Serous cystadenoma of pancreas
Serous cystadenoma of the pancreas (or microcystic adenoma) is an uncommon type of benign cystic pancreatic neoplasm.
There is a recognised strong female predilection (M:F ~ 1:4) and usually presents in middle age to elderly patients (>60 years of age).
Many patients are asymptomatic. 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 favour the pancreatic head.
- 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 low signal while cystic components themselves are 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 are observed without treatment 5. They are benign lesions and do not recur once resected 4.
General imaging differential considerations on cross sectional imaging include
- intraductal papillary mucinous tumour (IPMN) of pancreas: communicates with pancreatic ducts
- pancreatic pseudocyst
mucinous cystic neoplasm of pancreas (e.g. mucinous cystadenoma)
- calcification tends to be peripheral
- usually unilocular
- if multilocular type, individual cysts tend to be >20 mm in size
- cystic neoplasm (cystic pancreatic mass differential diagnosis)
- solid neoplasm
- nonepithelial pancreatic neoplasms
pancreatitis (mnemonic for the causes)
- gallstone pancreatitis
- interstitial oedematous pancreatitis
- necrotising pancreatitis
- haemorrhagic pancreatitis
- revised Atlanta classification of acute pancreatitis
- chronic pancreatitis
- Ascaris-induced pancreatitis
- tropical pancreatitis
- autoimmune pancreatitis
- emphysematous pancreatitis
- hereditary pancreatitis
- pancreatitis associated with cystic fibrosis
- segmental pancreatitis
- acute pancreatitis
- pancreatic atrophy
- pancreatic lipomatosis
- pancreatic trauma
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