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Imaging of Pancreatic Cystic Lesions. Dr Zaghouani. H, Pr Kraiem Ch Service d’imagerie Farhat Hached. 5th ARC of PAARS& 6th annuel Meeting of PAIRS 25-28 April Hammamet. INTRODUCTION.
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Imaging of Pancreatic Cystic Lesions Dr Zaghouani. H, Pr Kraiem Ch Service d’imagerie Farhat Hached 5th ARC of PAARS& 6th annuel Meeting of PAIRS 25-28 April Hammamet
INTRODUCTION • Incidence of pancreatic cystic lesions ranges from 1% to 25% in various studies; incidence in asymptomatic general populations is about 2.6%. • Wide spectrum of lesions including, non neoplastic, benign, borderline, and malignant pathologies. • Radiologists play an important role in detection, characterization, and follow-up of cystic lesions of the pancreas.
Clinical Presentation • A large number of pancreatic cysts are incidentally detected during imaging work-up for an unrelated medical problem.
Epidemiologic characteristics Brugge WR Eng J Med 2004
Morphologic Classification of Cystic Pancreatic Lesions Radiographics 2005 Nov-Dec;25(6):1471-84
Unilocular Cysts • Pseudocyst • IPMN occasionally • Unilocular serous cystadenoma • Lymphoepithelial cyst • Multiple: • Von Hippel-Lindau, Polycystic kidney disease
Pseudocyst • Generally symptomatic ( pain) • If asymptomatic, think about another Dx • History of acute or chronic pancreatitis • Almost always pseudocyst with this history • Look for associated findings • Pancreatic inflammation, parenchymal calcifications, atrophy, typical intraductal calcifications • Can communicate with pancreatic duct • Wide neck vs. narrow neck for IPMN • Wall can calcify • No mural nodules
Unilocular serous cystadenoma • When there is a unilocular cyst with a lobulated contour located in the head of the pancreas: unilocular macrocystic serous cystadenoma.
Multiple unilocular cysts in a patient withvon Hippel–Lindau disease
Microcystic Lesions • Serous cystadenoma • Only lesion included in this category • Benign tumor • “Grandmother Lesion” • May grow up to approx 4 mm/year • 70% cases demonstrate: • Polycystic/microcystic pattern • Collection of cysts (>6) • Range: few mm – 2 cm • External lobulations • Enhancing septa, walls • 30% demonstrate fibrous central • scar +/- stellate calcifcation • Other variants of these tumors • (macrocystic + oligocystic)
MR imaging: the microcysts :discrete foci with bright signal intensity on T2-weighted images. • Endoscopic US can help accurately depict these small microcysts as discrete small anechoic Areas. Radiographics 2005 Nov-Dec;25(6):1471-84
Macrocystic Lesions • Mucinous cystic neoplasms • Intraductal Papillary Mucinous Neoplasm (IPMN)
Mucinous cystic neoplasms • Mucinous cystadenomas & cystadenocarcinomas • Multilocular with complex internal architecture • May contain internal hemorrhage or debris • Peripheral Ca++ predictive of malignancy • Asymptomatic in 75% cases • If symptoms, usually due to mass effect • “Mother Lesion” • High potential for malignancy • Surgical resection yields good prognosis
Mucinous cystic neoplasms (mucinous cystadenomas) predominantly: - involve the body and tail of the pancreas • - they do not communicate with the pancreatic duct, they can cause partial pancreatic ductal obstruction.
Intraductal Papillary Mucinous Neoplasm (IPMN) • IPMNs classified : main duct, branch duct (side-branch), or mixed IPMNs, • Main duct IPMN is a morphologically distinct entity and cannot be included in the discussion of pancreatic cysts.
A side-branch IPMN or a mixed IPMN can have the morphologic features of a complex pancreatic cyst. • Identification of a septated cyst that communicates with the main pancreatic duct is highly suggestive of a side-branch or mixed IPMN.
MR cholangiopancreatography : the modality of choice for demonstrating: • - the morphologic features of the cyst (including septa and mural nodules), • - the presence of communication between the cystic lesion and the pancreatic duct, • - and evaluating the extent of pancreatic ductal dilatation.
The occurrence of malignancy is significantly higher in main duct and mixed IPMNs than in side-branch IPMNs. • In cases of side-branch IPMN with; • septated pancreatic cysts more than 3 cm in diameter • MDP> 7mm • mural nodules • have a high malignant potential
Other uncommon tumors (macrocystic lesions) include non functioning neuroendocrine tumors and rare congenital malformations such as lymphangiomas.
Cysts with a Solid Component • Unilocular or multilocular • True cystic tumors or solid pancreatic neoplasms with cystic component/degeneration • Wide DDx • Mucinous cystic neoplasms • IPMNs • Islet cell tumor • Solid pseudopapillary tumor (SPEN) • Adenocarcinoma • Metastasis • All malignant or have a high malignant potential • Surgical management
Management Pancreaticcysticlesions: Classification Kloppel et al.WHO Classification.2000
Management Pancreaticcysticlesions: Predictors of Malignancy Verbesy et al. Sur Clin N Am. 2010.
Management Cysticlesion in the pancreas Macrocyst Microcyst Cystwithsolid component unilocular No pancreatitis Nle amylase Pancreatitis Mucinouscystadenoma IPMN (branchduct or mixt) Serouscystadenoma Malignantneoplasm Pseudocyst Consider alternative dx Dilated MPD(IPMN) symptomatic asymptomatic asymptomatic symptomatic asymptomatic symptomatic Management depends on severalfactors Management depends on severalfactors Surgery or cyst aspiration Imaging follow-up Surgery Surgery Surgery
Management Pancreaticcysticlesions: Natural History and Prognosis • Cystic pancreatic neoplasms demonstrate better prognosis than adenocarcinoma with 5-year survival rates between 20-25%. • Natural history and prognosis of certain cystic pancreatic lesions with characteristic imaging findings is well-known; however, the fate of small (<3cm) lesions is still largely unknown. • Debate is still going on whether to resect or watch these indeterminate lesions. Verbesy et al. Sur Clin N Am. 2010.
Follow-up • No consensus • 6 month intervals for 1st year • Annual imaging for 3 years
TAKE HOME MESSAGES • Age & Gender • “Daughter Lesion”: SPEN • “Mother Lesion”: Mucinous cystic • “Grandmother Lesion”: Serous cystadenoma • Location • Head/neck for serous & side branch IMPN • Body/tail for mucinous cystic neoplasm • Calcification • Peripheral in mucinous cystic • Central in serous cystadenoma • Mural Nodularity (enhancement = neoplasm) • Duct communication (narrow neck) favors IPMN