Diagnostic Ultrasound - Abdomen and Pelvis

Mucinous Cystic Pancreatic Tumor
Diagnoses: Pancreas
Intraductal Papillary Mucinous Neoplasm
• Branch duct type: Grape-like clusters of small cysts
• Communicates with pancreatic duct
• Typically in head of pancreas or uncinate process
Macrocystic Variant of Serous Cystadenoma
• Unilocular cystic lesion usually in pancreatic head
• Typically shows thinner, nonenhancing imperceptible wall
Solid Pseudopapillary Tumor (SPN)
• Large solid and heterogeneously cystic mass commonly in
tail of pancreas
• Intratumoral hemorrhage is more typical of SPN; rarely
seen with MCN
• Typically in young women
Cystic Pancreatic Neuroendocrine Tumor
• Hypervascular mass with nonenhancing cystic/necrotic
components
• May be multiple
• May see metastatic disease in liver
PATHOLOGY
Staging, Grading, & Classification
• Tumors in this group include
○ Benign mucinous cystadenoma (72%)
○ Borderline mucinous cystic tumor (10.5%)
○ Mucinous cystic tumor with carcinoma in situ (5.5%)
○ Mucinous cystadenocarcinoma (12%)
• Any tumor in this group has potential to transform into
invasive carcinoma
Gross Pathologic & Surgical Features
• Large mass with thick fibrous capsule
• Mucin-containing cystic cavity
○ May be filled with thick mucoid
material/clear/green/blood-tinged fluid
• No communication with pancreatic duct
• Solid papillary projections may protrude into tumor
Microscopic Features
• Cysts lined by columnar mucin-producing epithelium
supported by ovarian-type stroma
○ Ovarian-type stroma distinguishes MCN from intraductal
papillary mucinous neoplasm (IPMN) with stroma ductal
in origin
• Epithelium ranges in grade from benign to carcinoma
○ Can have benign configurations adjacent to areas of
invasive carcinoma in same lesion
○ Biopsy to determine benign vs. malignant disease is
therefore unreliable
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Often asymptomatic
○ May present with epigastric pain, palpable mass, or
fullness
Demographics
• Age
○ Mean age: 50 years
○ Range: 20-82 years
• Gender
○ M:F = 1:20
• Epidemiology
○ 10% of cystic pancreatic tumors
○ 1% of pancreatic neoplasms
Natural History & Prognosis
• Invariably transforms into cystadenocarcinoma
• Resection in absence of invasive carcinoma usually curative
• 0% risk of recurrence
• 5-year survival rate for invasive MCN 75%
Treatment
• All tumors in this class are considered surgical lesions
○ Typically seen in younger patient population and
nonoperative management would require years of highcost,
high-resolution imaging
○ Additionally, imaging and biopsy are unreliable in
excluding invasive elements
○ Even benign lesions have future potential for malignant
conversion
• Tumors < 4 cm without mural nodule
○ May perform laparoscopic procedure
○ Parenchyma-sparing resections (e.g., middle
pancreatectomy) and distal pancreatectomy with spleen
preservation should be considered
• Observation may be considered in elderly frail patients if
unfit for surgery
DIAGNOSTIC CHECKLIST
Consider
• Differentiate from other cystic pancreatic lesions
• EUS and cyst aspiration for further evaluation
Image Interpretation Pearls
• Large, round, solitary, encapsulated uni- or multiloculated
cystic mass with enhancing wall and internal septations
SELECTED REFERENCES
1. Khashab MA et al: Should we do EUS/FNA on patients with pancreatic cysts?
The incremental diagnostic yield of EUS over CT/MRI for prediction of cystic
neoplasms. Pancreas. 42(4):717-21, 2013
2. Sahani DV et al: Diagnosis and management of cystic pancreatic lesions. AJR
Am J Roentgenol. 200(2):343-54, 2013
3. Dewhurst CE et al: Cystic tumors of the pancreas: imaging and management.
Radiol Clin North Am. 50(3):467-86, 2012
4. Tanaka M et al: International consensus guidelines 2012 for the
management of IPMN and MCN of the pancreas. Pancreatology. 12(3):183-
97, 2012
5. Sakorafas GH et al: Primary pancreatic cystic neoplasms revisited: part II.
Mucinous cystic neoplasms. Surg Oncol. 20(2):e93-101, 2011
6. Reddy RP et al: Pancreatic mucinous cystic neoplasm defined by ovarian
stroma: demographics, clinical features, and prevalence of cancer. Clin
Gastroenterol Hepatol. 2(11):1026-31, 2004
368