Diagnostic Ultrasound - Abdomen and Pelvis

Serous Cystadenoma of Pancreas
Diagnoses: Pancreas
• SBD type lesion simulates serous microcystic adenoma due
to presence of dilated small branch ducts
○ Grape-like cluster of small cysts
○ Communicates with the MPD
○ May be multiple
• Can show pancreatic ductal dilatation
Cystic Neuroendocrine Tumor
• Solid mass with no pancreatic ductal dilatation
• May show cystic components due to degeneration or
central necrosis which can contain hemorrhagic debris
• Intratumoral hemorrhage rare with SCA
Ductal Pancreatic Carcinoma
• More common tumor than serous cystadenoma
• Rarely shows necrosis, or appears cystic due to fibrosis
• Lack of tumoral calcification
• Shows pancreatic &/or common bile ductal dilatation;
vascular encasement ± regional/distant metastases
Solid Pseudopapillary Neoplasm
• Rare solid and cystic tumor with thick capsule and areas of
necrosis and hemorrhage
• Intratumoral hemorrhage rare with SCA
• Typically in young women
PATHOLOGY
General Features
• Associated abnormalities
○ von Hippel-Lindau disease: May have multiple SCAs
• In general no malignant potential
Gross Pathologic & Surgical Features
• Well-circumscribed, round/ovoid, cystic mass with lobulated
margin due to bulging cysts
• Macroscopic cut section
○ Spongy appearance due to many small cysts (1-20 mm)
○ Fluid in cysts : Typically clear with no mucoid plugs
– Rarely hemorrhagic in nature
○ Thin septa radiating from central scar ± dystrophic
calcification
Microscopic Features
• Cysts lined by small cuboidal epithelial cells with clear
cytoplasm and minimal mucin
○ Glycogen-rich; no cytologic atypia nor mitotic figures
• Positive staining for epithelial membrane antigen &
cytokeratin of low and high molecular weights
• Fibrovascular septa
• Adjacent pancreatic tissue: Normal or focally atrophic
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Typically asymptomatic or vague epigastric pain
○ May present with nausea, vomiting, weight loss, palpable
mass, jaundice
○ Other signs/symptoms of mass effect on adjacent
structures (stomach & bowel)
Demographics
• Age
○ Middle & elderly age group (more common)
○ Mean age 61.5 years
• Gender
○ M:F = 1:4
• Epidemiology
○ Cystic pancreatic neoplasms are rare
○ Accounts for 20% of all cystic pancreatic lesions; only 1%
of all pancreatic neoplasms
Natural History & Prognosis
• Clinical practice assumes benign, slow-growing course
○ Most remain static over time with slow growth rate (~
0.12 cm/year) and no complications
• Rare tumors may behave aggressively or become
symptomatic (usually large lesions and location in the head
of the pancreas)
○ Tumors > 4cm grow faster (~ 2 cm/year)
○ Potential complications: CBD obstruction or obstructive
chronic pancreatitis, bowel obstruction; invasion of
surrounding structures or vessels
○ Very rarely metastases to lymph nodes or distant organs
• Prognosis
○ Excellent: Classically thought to have no malignant
potential
○ However, rare aggressive subtypes can be locally
aggressive or malignant (0.8%)
○ Good prognosis after complete excision with negative
surgical margins, in symptomatic or aggressive cases
○ May recur after incomplete resection
Treatment
• Nonoperative management if asymptomatic, small, and
confidently diagnosed
○ Imaging surveillance at 6-12 month intervals until
stability demonstrated over 2 year period
• Symptomatic & large tumors → complete surgical excision
○ No imaging surveillance necessary if negative surgical
margins
DIAGNOSTIC CHECKLIST
Consider
• Differentiate from other cystic pancreatic lesions such as
pseudocysts or cystic neoplasms that have malignant
potential
Image Interpretation Pearls
• Well-demarcated, lobulated cystic lesion composed of
innumerable small cysts (1-20 mm) separated by thin
hypervascular septa
SELECTED REFERENCES
1. But DY et al: To fine needle aspiration or not? An endosonographer's
approach to pancreatic cystic lesions. Endosc Ultrasound. 3(2):82-90, 2014
2. Dewhurst CE et al: Cystic tumors of the pancreas: imaging and management.
Radiol Clin North Am. 50(3):467-86, 2012
3. Kucera JN et al: Cystic lesions of the pancreas: radiologic-endosonographic
correlation. Radiographics. 32(7):E283-301, 2012
4. Choi JY et al: Typical and atypical manifestations of serous cystadenoma of
the pancreas: imaging findings with pathologic correlation. AJR Am J
Roentgenol. 193(1):136-42, 2009
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