IMAGING IN CYSTIC LESIONS OF PANCREAS(agnyayshay / pachak granthi)

Clinical Features Majority of pancreatic cysts are incidentally

detected i.e. they are asymptomatic. Symptomatic cysts are most likely to

manifest with abdominal pain. Jaundice or recurrent pancreatitis often

indicates that the lesion is either in communication with the pancreatic ductal system or obstructing the pancreatic or biliary duct.

Pseudocysts typically occur with acute pancreatitis or may develop insidiously in the setting of chronic pancreatitis.

Classification of Cystic Pancreatic Lesions Pseudocyst Common cystic pancreatic neoplasms

Serous cystadenoma Mucinous cystic neoplasm IPMN

Rare cystic pancreatic neoplasms Solid pseudo papillary tumor Acinar cell cystadenocarcinoma Lymphangioma Hemangioma Paraganglioma

Classification of Cystic Pancreatic Lesions (cont) Solid pancreatic lesions with cystic

degeneration Pancreatic adenocarcinoma Cystic islet cell tumor (insulinoma,

glucagonoma, gastrinoma) Metastasis Cystic teratoma Sarcoma

True epithelial cystsAssociated with von Hippel–Lindau disease,

autosomal -dominant polycystic kidney disease, and cystic fibrosis

Pathologic Classification of Pancreatic Neoplasms

Epithelial Neoplasms

Exocrine tumors

Duct cell origin -Adenocarcinoma -Adenocarcinoma

variants( Mucinous adenocarcinoma)a

Micro cystic adenoma Mucinous cystic tumora

IPMT

Acinar cell origin - Acinar cell

carcinoma - Acinar cell

cystadenocarcinomaa

Solid papillary epithelial neoplasma

Giant cell tumora

Pathologic Classification of Pancreatic Neoplasms (cont..)

Endocrine tumors

Insulinomaa

Gastrinomaa

Glucagonoma VIPoma

Somatostatinoma Polypeptidoma

Carcinoid tumor

Pheochromocytoma

Nonepithelial Neoplasms

Sarcomaa

Metastasesa

Lymphoma

Four Morphologic Types of Cystic Lesions of the Pancreas

Unilocular Cysts Pseudocyst IPMN occasionally Unilocular serous cystadenoma Lymphoepithelial cyst Multiple

von Hippel-Lindau Pseudocysts

Pseudocyst Sharply marginated Unilocular or multilocular

fluid-filled pancreatic or peripancreatic collections that are encapsulated by fibrous tissue and usually form after inflammation, necrosis, or hemorrhage related to acute pancreatitis or trauma.

In acute pancreatitis, there is mesenteric edema and peripancreatic stranding.

In chronic pancreatitis, there may be associated pancreatic parenchymal calcifications.

Older cysts tend to have thicker walls that may contain calcium.

These cysts can be located anywhere within the pancreas but predominantly involve the body or tail of the organ.

IMAGING IN PSEUDOCYST

CONVENTIONAL( OLD IS GOLD !!)A) SIGNS OF ACUTE PANCREATITITS1.) Duodenal ileus ; the duodenal folds may be

thickened. 2.) Gasless abdomen3.) Sentinel loop 4.)Absent left psoas shadow .5.)Colon cut-off sign', where the dilated transverse

colon becomes abruptly gasless in the region of the splenic flexure.

B.) SIGNS OF CHRONIC PANCREATITITS1.) Calcification.

Acute and Chronic pancreatitis

Colon cut off sign and ileus

Imaging in pseudocyst(cont.)

ULTRASOUND Real Time Usually solitary unilocular cyst (body or tail),

multilocular in 6% of cases Fluid-debris level & internal echoes due to

autolysis(blood clot/cellular debris) Septations (rare; sign of infection or

hemorrhage) Dilated pancreatic duct & CBD may be seen Calcification of pancreas (chronic

pancreatitis)

USG….

Imaging in pseudocyst(cont.)CT-PLAIN AND CONTRAST….NECT Round or oval, homogeneous, hypodense lesion ("mature"

pseudocyst) Hemorrhagic/ Infected pseudocyst: Lobulated , heterogeneous,

mixed density lesion ± Pancreatic calcification;(MPD) & common bile duct (CBD)

dilatationCECT Enhancement of thin rim of fibrous capsule No enhancement of pseudocyst contents Gas within pseudocyst suggests superimposed infection,

decompression of pseudocyst into pancreatic duct, stomach or bowel.

Pseudo aneurysms can be caused by or simulate a pseudocyst. CECT shows enhancement like adjacent blood vessels

CT…

CT…ATYPICAL

CT…Complications

MRI IN PSEUDOCYST

MR Findings T1WI: Hypointense T2WI Hyperintense (fluid) Mixed intensity (fluid + debris)T1 C+: May show enhancement of fibrous

capsuleMRCP: Hyperintense cyst contiguous with dilatedpancreatic duct

MRI IN PSEUDOCYST(cont)

Axial T2-weighted MR image complex cyst with a fluid-debris level in head.

MRI IN PSEUDOCYST(cont)

OTHER CAUSES OF UNILOCULAR CYSTS Side-branch IPMN manifesting as a

Unilocular cyst.

Multiple unilocular cysts in a patient withvon Hippel–Lindau disease

CYSTIC NEOPLASMS•The diagnosis of a cystic neoplasm should be considered when there is no history of pancreatitis or trauma.•Morphological characteristics of a cystic neoplasm are: - thick irregular rim, - septations - solid components - dilated pancreatic duct > 3mm and calcifications.•Fluid aspirated from a cyst with an HIGH amylase level•It is important to make the diagnosis of a serous cystic neoplasm, since this is the only tumor that has no malignant potential.

Microcystic Lesions-Serous cystadenoma

•Benign tumor, but large tumors have a tendency to increase in size and cause symptoms.• Typically seen in 'Grandma' .•Microcystic or honey-combed cyst with central scar (30%) and calcifications (18%)•Macrocystic in 10% and difficult to differentiate from pseudocyst and mucinous cystic neoplasm .•Lobulated surface .•No communication between cysts and pancreatic duct.•Hypervascular enhancement is sometimes seen and can look like cystic neuroendocrine tumor

Serous cystadenoma

Serous cystadenoma-cont..

Hypodense lesion with central calcification&enhancement of septae

T2WI fatsat shows a lobuated hyperintense lesion with central scar,characteristic of SCN.

Serous cystadenoma(macrocystic variant)

Macrocystic Lesions

Mucinous cystic neoplasms Intraductal Papillary Mucinous

Neoplasm (IPMN)

MUCINOUS CYSTIC NEOPLASMS

Premalignant tumor - may transform into a mucinous cystadenocarcinoma

Exclusively seen in women - Typically in 'Mother' - median age: 40-50 years

Macrocystic with thick wall septations and peripheral calcifications

Peripheral calcifications seen in 25%. This finding allows you to make a specific diagnosis

Location in the tail and body of the pancreas (95%).

Most are symptomatic, presenting with nondescript abdominal pain

Mucinous cystadenoma manifesting as a multiseptated cyst

MUCINOUS CYSTIC NEOPLASMS (cont..)

Mucinous cystadenoCARCINOMA

D/D b/w Mucinous cystadenoma and CARCINOMA

•Mucinous cystadenocarcinoma manifest at MR imaging as large complex cystic pancreatic lesions.• They may be distinguished from Mucinous cystadenoma by the presence of intracystic enhancing soft tissue.•Hence, any enhancing soft tissue within a cystic neoplasm depicted on MR images is considered an indication for resection

D/D b/w Mucinous cystadenoma and CARCINOMAD/D b/w Mucinous cystadenoma and CARCINOMA (cont..)

Axial T2-weighted MR image shows a large, complex cystic lesion in head

Contrast-enhanced MR images show enhancing mural soft-tissue elements projecting toward the cyst center.

Intraductal Papillary Mucinous Neoplasm

•Mucin producing tumor in main pancreatic duct or branch-duct.•Location: pancreatic head >> tail and corpus.•Must have communication with pancreatic duct.•Best seen with MRCP.•Can be multifocal.•Main-duct IPMN has imaging features distinct from branch-type.•Branch-duct type can look like other cystic neoplasms

Intraductal Papillary Mucinous Neoplasm..Main duct type..

Extremely widened main pancreatic duct (red arrow).

Intraductal Papillary Mucinous Neoplasm..Branch duct type..•"Multicystic" lesion in uncinate process/head contiguous with dilated MPD("grape-like"clusters or tubes & arcs)

Intraductal Papillary Mucinous Neoplasm..

SOMETIMES THERE IS A MIXED TYPE.THE MRCP SHOWS BOTH A MAIN-DUCT AS WELL AS A BRANCH-DUCT IPMN (ARROW)..

Intraductal Papillary Mucinous Neoplasm..MALIGNANT

Signs of malignancy are:•Pancreatic duct > 8 mm•Solid node in duct.•Mass around the pancreatic duct.•Enlarged choledochal duct.

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

Solid pseudopapillary tumor manifesting as a cyst with a solid component

•Very uncommon neoplasm seen in women 20-30 years (Daughter). Solid and cystic neoplasm with capsule and with early 'hemangioma-like' enhancement. Sometimes intratumoral hemorrhage

Metastases manifesting as cysts with solid components

Neuroendocrine tumor with cystic degeneration

•Non-functioning endocrine neoplasm Also called islet cell tumor.•Hypervascular with ring-enhancement. This is unlike serous cystic neoplasms that enhance from the center and more solid

NEOPLASMS IN NUTSHELL

MORPHOLOGY

REPORTING POINTS-“BHULNA MANA HAI” !!

Endoscopic US Can provide detailed morphologic evaluation of

cystic lesions For detecting malignant tumors:▪ Sensitivity: 40%▪ Specificity: 100%▪ Accuracy: 50%

Advantage of aspiration of contents, sampling of cyst wall, septa or mural nodule Less potential for tumor seeding than

percutaneous sampling Highly viscous contents (mucin) consistent with

mucinous neoplasm Tumor markers, cytologic analysis, biochemical

markers, fluid amylase

MRI VS CT- DEBATE OF CENTURY!! Advantage of CT over MRI Better depicts a central

calcification in SCN or peripheral calcification in a mucinous cystic neoplasm (MCN).

MRI VS CT- DEBATE OF CENTURY!! AdvantageS of MRI over CT.. 1. MR with heavily weighted T2WI and

MRCP will better demonstrate the cystic nature and the internal structure of the cyst and has the advantage of demonstrating the relationship of the cyst to the pancreatic duct as is seen in IPMN.

2. MRI better shows the central scar in SCN.

3. Presence of internal dependent debris appears to be a highly specific MR finding for the diagnosis of pancreatic pseudocyst.

Pearls

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

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