serous cystadenoma of pancreas

Serous cystadenoma of the pancreas, also referred as microcystic adenoma, is an uncommon type of benign cystic pancreatic neoplasm.

Epidemiology

There is a recognized strong female predilection (M:F ~ 1:4) and usually presents in middle age to elderly patients (>60 years of age).

Clinical presentation

Most patients are asymptomatic . Some may present with pain, weight loss, jaundice, or a palpable mass .

Pathology

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) .

Most individual cysts are typically <10 mm .

Three morphological patterns have been described :

• 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).

Associations

• von Hippel Lindau (vHL) disease: can be multiple or diffuse and present at a younger age

Location

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% .

Radiographic features

Plain radiograph

• nonspecific and will usually be normal
• may demonstrate amorphous central calcification overlying the pancreas

Ultrasound

• nonspecific hypoechoic mass in the pancreatic head region, possibly with internal echoes indicating microcysts (the oligocystic subtype may demonstrate individually identifiable cysts )

CT 

• 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)

MRI

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

Excluding the absence of communication with the main pancreatic duct, visualization of the lesion will not be facilitated by secretin-enhanced MRCP (SMRCP or MRCP-S) .

Angiography

• may show enhancement due to hypervascular components

Treatment and prognosis

Most lesions should be observed without treatment, unless there is diagnostic uncertainty or significant associated symptomatology . They are benign lesions and do not recur once resected .

Differential diagnosis

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

Siehe auch:

• Pankreaspseudozyste
• zystische Pankreasläsionen
• intraduktale papillär muzinöse Neoplasie
• muzinöses Zystadenom
• Pankreaszysten
• muzinös zystische Neoplasien des Pankreas
• mikrozystisches seröres Zystadenom des Pankreas

und weiter:

• Kystom
• Zystadenom
• muzinöses Zystadenom des Pankreas
• seröses Zystadenom
• seröses Zystadenokarzinom Pankreas
• pancreatic cystadenoma
• serous cystadenocarcinomas