Serous cystadenoma of the pancreas

Last revised by Mostafa Elfeky on 31 Jul 2023

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). 

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

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) 14,15.

  • may show enhancement due to hypervascular components 4

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:

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