1
Q
Pancreatic AdenoCA (ductal adenoCA)
Makes up what percent of all pancreatic tumors?
Seen in what population? Risk factors?
What is included in a pancreatic-mass CT protocol? What phase exhibits greatest conspicuity for detection of pancreatic adenoCA?
Most common location?
Imaging Appearance?
What is it almost always associated with?
When does it present?
Treatment?
A
- Pancreatic ductal adenocarcinoma makes up 80-90% of all pancreatic tumors. It is typically seen in patients over age 60, with a slight male predominance. Risk factors include smoking, alcohol, and chronic pancreatitis.
- A pancreatic-mass CT includes unenhanced, late arterial phase, and portal venous phase images. The late arterial phase (pancreatic parenchymal phase) has the greatest conspicuity for detecting the hypoenhancing tumor against the background enhancing pancreas.
- The most common location of ductal adenocarcinoma is the pancreatic head.
- The classic appearance is a hypodense (CT), T1 hypointense (MR), ill-defined, hypovascular mass causing ductal obstruction and atrophy of the pancreatic tail. The double duct sign describes dilation of both the pancreatic duct and the common bile duct.
- Since pancreatic adenocarcinoma is almost always associated with a dilated pancreatic duct, an alternative diagnosis should be strongly considered if there is a pancreatic mass with no ductal dilation.
- Conversely, if the double duct sign is present but no mass is visible, one should still be suspicious for pancreatic adenocarcinoma. Approximately 10% of cases will be isoattenuating relative to the pancreas in the pancreatic parenchymal (late arterial) phase and thus extremely difficult to directly detect.
- Most cancers present at an advanced, unresectable stage. Unresectable tumors show encasement (>180 degrees circumference) of the SMA, extensive venous invasion, or evidence of metastasis.
- For lower-stage tumors, complete surgical resection is the only chance for cure. A resectable tumor features no evidence of celiac, SMA, or portal venous invasion. Limited extension to the duodenum, distal stomach, or CBD does not preclude resection, as these structures are resected during the Whipple procedure. Limited venous extension may be resectable.
2
Q
If there is a pancreatic mass with no ductal dilation, what should be considered?
A
Since pancreatic adenocarcinoma is almost always associated with a dilated pancreatic duct, an alternative diagnosis should be strongly considered if there is a pancreatic mass with no ductal dilation, such as:
- Autoimmune pancreatitis.
- Groove pancreatitis.
- Cystic pancreatic tumor.
- Neuroendocrine tumor.
- Duodenal gastrointestinal stromal tumor (GIST).
- Peripancreatic lymph node.
- Pancreatic metastasis (e.g., renal cell, thyroid, or melanoma).
- Lymphoma.
3
Q
Pancreatic Acinar Cell CA
What is it?
Malignant cells produce a large amount of what?
This leads to what presentation?
A
- Acinar cell carcinoma is a rare, aggressive variant of pancreatic adenocarcinoma, exclusively seen in elderly males.
- The malignant cells produce a large amount of lipase to cause the clinical triad of lipase hypersecretion syndrome: Subcutaneous fat necrosis, bone infarcts causing polyarthralgias, and eosinophilia.
4
Q
Pancreatic Serous Cystadenoma
What is it? Found it what population?
Cyst morphology?
What makes it unique? How to differentiate say between this and adenoCA?
Classic imaging feature?
A
Raffi Mnemonic: grandmas are so “serious” (i.e. serous) - they also have many small cysts, they are hypervascular, and grumpy central stellate calcification!
- Serous cystadenoma is a benign tumor that occurs in elderly women and has been nicknamed the grandmother tumor.
- It consists of many small cysts (>6 cysts that are <2 cm) that may have a solid appearance on CT due to apposition of many cyst walls. MR is useful to show the cystic nature of the lesion.
- Serous cystadenoma is hypervascular, unique among cystic pancreatic tumors.
- Unlike adenocarcinoma, serous cystadenoma does not cause pancreatic duct dilation or tail atrophy.
- A classic imaging feature is central stellate calcification.
5
Q
Overview of Pancreatic Neoplasms
- Solid epithelial neoplasms
- Cystic epithelial neoplasms
- Endocrine neoplasms
A
- Solid epithelial neoplasms
- Ductal adenoCA
- Acinar cell CA
- Cystic epithelial neoplasms
- SPEN - young women
- Mucinous cystic - middle-aged women (Mom)
- Serous cystic - “serious grandmother”
- IPMN - elderly males
- Endocrine neoplasms
- Insulinoma
- Gastrinoma
- Glucagonoma
- VIPoma
- Somatostatinoma
6
Q
Pancreatic Mucinous Cystic Neoplasm
What is it? Seen most commonly in what population?
Malignant potential? Treatment?
The number of cysts and size? Where is pancreas is it usually formed?
Does it have a capsule?
A
- Mucinous cystic neoplasm affects middle-aged women and has therefore been nicknamed the Mother tumor.
- Mucinous cystic neoplasm is benign but does have Malignant potential. Treatment is typically resection due to malignant potential.
- The tumor consists of a single or a few large cysts (<6 cysts that are >2 cm) and typically occurs in the pancreatic body and tail.
- Mucinous cystic neoplasm has a capsule. The only other pancreatic tumor with a capsule is SPEN.
7
Q
Solid and Papillary Epithelial Neoplasm (SPEN)
What is it? Seen in what population?
Malignant potential? Treatment?
Imaging? Typical finding? Does it have a capsule?
A
Raffi Mnemonic - A little girl named SPEN!
- Solid and papillary epithelial neoplasm (SPEN) occurs in young women and children and is nicknamed the daughter tumor. It may be a rare cause of abdominal pain.
- It has a low malignant potential and is typically resected.
- On imaging, SPEN appears as a large mass with heterogeneous solid and cystic areas. Hemorrhage is typical. SPEN features a capsule, as does mucinous cystic neoplasm.
8
Q
Intraductal Papillary Mucinous Neoplasm (IPMN)
What is it? Seen in what population?
Indolent or aggressive? Which subtype has a greater malignant potential? What feature should raise concern for malignancy?
Classic endoscopic finding? Imaging appearance?
Treatment?
A
Raffi Mnemonic - ipMAN - grandfather tumor (that smells fishy! - endoscopic feature)
- Intraductal papillary mucinous neoplasm IPMN occurs most commonly in elderly males and is nicknamed the grandfather tumor, although these tumors exhibit the greatest age and sex variability of the cystic pancreatic neoplasms.
- IPMN features a spectrum of biological behavior from benign to indolent to aggressive carcinoma. IPMNs may arise from the main pancreatic duct or a side branch. The main duct IPMNs have greater malignant potential.
- The classic appearance on endoscopy is a fish-mouth papilla pouring out mucin. Cross-sectional imaging shows a cystic intrapancreatic lesion in contiguity with the duct or side branch. Any nodular or enhancing component should raise concern for malignancy.
- The recommended imaging follow-up and criteria for resectability are controversial. Current guidelines published in 2006 recommend following simple pancreatic cysts 1 cm annually by imaging(MR). However, up to 40% of elderly males have a pancreatic cyst, suggesting that they may be an acquired condition of aging rather than a premalignancy.
- In general, a suspected IPMN is resected if it is >3 cm in size, if there is a mural nodule, or if there is associated dilation of the pancreatic duct to >10 mm.
9
Q
What do non-hyperfunctioning pancreatic endocrine neoplasms often undergo that can be seen on imaging?
What phase are they best seen on?
What should be considered in a case of a hypervascular liver mass with an associated pancreatic mass?
A
- Non-hyperfunctioning tumors tend to be larger at diagnosis. These tumors may undergo cystic change and should be considered in the differential of a cystic pancreatic neoplasm. There is often central necrosis and calcification in these large tumors as well.
- Pancreatic endocrine tumors tend to be hypervascular and are best seen in the late arterial phase. Most are solid unless large. A hypervascular liver mass with an associated pancreatic mass is most likely a metastatic pancreatic endocrine neoplasm.
10
Q
A hypervascular liver mass with an associated pancreatic mass is most what?
A
- A hypervascular liver mass with an associated pancreatic mass is most likely a metastatic pancreatic endocrine neoplasm.
11
Q
Insulinoma
Prevalence vs other pancreatic neuroendocrine tumors? Prognosis?
What is the Whipple triad?
A
- Insulinoma is the most common pancreatic endocrine tumor. Due to symptoms of hypoglycemia, insulinomas tend to present early and have the best prognosis of all neuroendocrine tumors, with only 10% demonstrating malignant behavior.
- The Whipple triad describes the clinical symptoms of insulinoma: Hypoglycemia, clinical symptoms of hypoglycemia, and alleviation of symptoms after administration of glucose.
12
Q
Gastrinoma
Prevalence vs other pancreatic endocrine neoplasms
What syndrome does it cause?
What is it associated with and when it is associated with this what does the gastrinoma tend to do?
What is the gastrinoma triangle?
What else can form in the stomach?
A
- Gastrinoma causes hypersecretion of gastric acid resulting in Zollinger-Ellison syndrome. gastrinoma is the second most common pancreatic endocrine tumor. Gastrinoma is associated with multiple endocrine neoplasia MEN type 1. When associated with MEN-1, gastrinomas tend to be multiple and located in the duodenum rather than the pancreas.
- The gastrinoma triangle describes the typical location of gastrinomas, in an area bounded by the junction of the cystic duct and CBD, the duodenum inferiorly, and the neck/body of the pancreas medially.
- High gastrin levels may cause the formation of carcinoid tumors in the stomach, which may regress after the gastrinoma is resected.
13
Q
Normal Pancreatic Ductal Anatomy
Mnemonic for normal anatomy
What anatomy is always constant?
A
- Normally, the main pancreatic duct drains to the major papilla (the ampulla of vater) through the duct of Wirsung, while the duct of Santorini drains to the minor papilla.
- Mnemonic for normal anatomy: Santorini is Superior and drains to Small (minor) papilla.
- The following anatomy is always constant, regardless of whether an anomaly is present:
- The common bile duct always drains to the major papilla where it meets the duct of Wirsung.
- The main pancreatic duct always drains the pancreatic tail
- The duct of Santorini always drains to the minor papilla.
14
Q
What is the most common congenital pancreatic anomaly?
What causes it?
Pancreatic excretion path?
What can it cause?
Imaging sign?
A
- Pancreas divisum is the most common congenital pancreatic anomaly. It is caused by failure of fusion of ventral and dorsal pancreatic ducts. The ventral duct (Wirsung) only drains a portion of the pancreas while the majority of the pancreatic exocrine gland output is drained through the smaller duct of Santorini into the minor papilla.
- Pancreas divisum may be a cause of pancreatitis due to obstruction at the minor papilla from a Santorinicele. A Santorinicele is a focal dilation of the terminal duct of Santorini.
- The crossing sign describes the CBD crossing over the main duct to join the duct of Wirsung.
15
Q
Annular Pancreas
What is it? How does it form?
What can it cause in an adult?
Imaging appearance in a neonate?
A
- Annular pancreas is a rare congenital anomaly where a portion of the pancreas wraps completely around the duodenum, secondary to incomplete rotation of the ventral pancreatic bud.
- In an adult, the annular pancreas can cause pancreatitis, peptic ulcer disease, and duodenal obstruction. In a neonate, it can cause duodenal obstruction and is in the differential for the double bubble sign.
16
Q
What is the common channel syndome/pancreaticobiliary maljunction?
A
- Normally the common bile duct and duct of Wirsung both drain to the major papilla, where there is usually a thin septum separating these two systems.
- In common channel syndrome, also known as pancreaticobiliary maljunction, the distal CBD and pancreatic duct are missing the septum, allowing reflux between the two systems.
- Common channel syndrome may be in the spectrum of choledochal cyst disease with the common channel representing a very mild form of choledochocele. Common channel syndrome may predispose to cholangiocarcinoma, but this is rare and controversial.
17
Q
What are the systemic diseases that affect the pancreas?
A
- VHL
- CF
- Schwachman-Diamond
- Obesity and exogenous steroid use
- Hemochromatosis
18
Q
What are the pancreatic manifestations of VHL
A
- von Hippel-Lindau is an inherited multisystemic disease with increased risk of multiple malignancies and formation of cysts in various organs including the pancreas.
- Pancreatic neoplasms seen in von Hippel-Lindau include serous cystadenoma and pancreatic neuroendocrine tumors.
19
Q
What are the pancreatic manifestations of CF?
A
- CF is the most common cause of childhood pancreatic atrophy.
- CF can cause either fatty atrophy of the pancreas or pancreatic cystosis (diffuse replacement of the pancreas with innumerable cysts).
20
Q
What is Schwachman-Diamond disorder?
A
- Schwachman-Diamond is a rare inherited disorder characterized by diffuse fatty replacement of the pancreas, resultant pancreatic exocrine insufficiency, neutropenia, and bone dysplasia.
- Schwachman-Diamond is the second-most common cause of childhood pancreatic atrophy.
21
Q
Both obesity and exogenous steroid use can cause what to the pancreas?
A
Fatty atrophy
22
Q
Intrapancreatic Accessory Spleen
What does it mimic?
Imaging?
How to diagnose? How to confirm the diagnosis in ambiguous cases?
A
- Intrapancreatic accessory spleen is a benign mimic of a hypervascular pancreatic neoplasm.
- On imaging, an intrapancreatic spleen typically is a small (1-3 cm), well-defined mass usually found in the pancreatic tail. It follows the density, signal intensity, and enhancement of the spleen on all CT and MR sequences.
- MRI is usually diagnostic. Either technetium-99m sulfur colloid or technetium-99m RBC scintigraphy can confirm the diagnosis in ambiguous cases.
23
Q
Pancreatitis - CT protocol and role of imaging
A
- Imaging of pancreatitis is optimally performed in the pancreatic parenchymal phase (late arterial: ~40 seconds after contrast injection), which is the most sensitive timing to detect subtle areas of decreased enhancement suggestive of necrosis.
- CT is key for pancreatitis imaging. In addition to often identifying an etiology of the pancreatitis, CT can grade severity, detect complications, and guide possible percutaneous interventions.
- CT imaging is not indicated in patients with clinical diagnosis of mild acute pancreatitis, especially if they are improving. CT imaging may be negative or show a mildly edematous pancreas in these cases.
24
Q
Acute Pancreatitis
What is it?
Clinical outcome?
Most common causes?
Grading systems?
A
- Pancreatitis is inflammation of the pancreas, which may be due to a wide variety of etiologies that share a final common pathway of premature activation of pancreatic enzymes and resultant autodigestion of pancreatic parenchyma.
- Pancreatitis may range in severity from mild self-limited disease to necrotizing pancreatitis resulting in multi-organ failure and death.
- Acute pancreatitis is most commonly caused by alcohol or an obstructing gallstone.
- Acute pancreatitis can be classified either with the Balthazar grading system or by the CT severity index.
25
Balthazar grading system
A: Normal-appearing pancreas
B: Focal or diffuse pancreatic enlargement
C: mild peripancreatic inflammatory changes
D: Single fluid collection
E: Two or more fluid collections
* 0% mortality, 4% morbidity for grades A, B, and C.
* 14% mortality, 54% morbidity for grades D and E (a fluid collection is a poor prognostic indicator).
26
CT Severity index (CTSI) grading system
* CTSI integrates the Balthazar grading system with the degree of necrosis:
Assigns 0-4 points for Balthazar A-E, with 0 points for Balthazar A and 4 points for Balthazar E.
Adds 0-6 points for necrosis to create a total score from 0-10.
0 points: 0% necrosis
2 points: \<30% necrosis
4 points: 30-50% necrosis
6 points: \>50% necrosis
CTSI 0-3: 3% mortality, 8% morbidity
CTSI 7-10: 17% mortality, 92% morbidity
27
What are the pancreatic and peripancreatic complications of acute pancreatitis?
* **Pancreatic necrosis**: on imaging, pancreatic necrosis appears as a focal or diffuse area of non-enhancing pancreatic parenchyma. Evaluation of necrosis is best performed 48-72 hours after onset of acute pancreatitis. Late arterial phase imaging has the highest sensitivity for detecting pancreatic necrosis. Patients with pancreatic necrosis are at increased risk for infection and severe morbidity.
* **Fluid collections**: Peripancreatic fluid may resolve or may evolve either into peripancreatic abscess or pseudocyst.
* **Pseudocyst**: A pancreatic pseudocyst is a collection of pancreatic enzymes and fluid enclosed by a fibrous wall lacking an epithelial lining. The fibrous wall usually takes about 4-6 weeks to mature.
* **Pancreatic abscess**: Pancreatic abscess is a purulent collection featuring thicker, more irregular walls compared to a pseudocyst. gas locules may be present within the abscess.
28
What are the extrapancreatic complications of acute pancreatitis?
* **Extrapancreatic** **pseudocyst** may occur nearly anywhere below the diaphragm and should always be considered in the differential of a cystic structure in a patient with a history of pancreatitis. In particular, an intrasplenic pseudocyst may lead to intrasplenic hemorrhage.
* **Perihilar renal inflammation**, which may lead to venous compression or thrombosis.
* **Bowel involvement**, especially of the transverse colon.
29
Acute pancreatitis can cause secondary inflammation of adjacent vessels.
What are the vascular complications of acute pancreatitis?
1. **Arterial bleeding**, most commonly due to erosion into the splenic artery.
2. **Pseudoaneurysm**, most commonly of the splenic artery.
3. **Venous thrombosis**, most commonly splenic vein thrombosis, which may lead to **portal hypertension**.
30
Chronic Pancreatitis
What is it?
Cause? Another rare cause?
Pathognomonic appearance?
* Chronic pancreatitis, most commonly from long-term alcohol abuse, causes irreversible pancreatic damage.
* A much less common cause of chronic pancreatitis is pancreas divisum.
* Calcifications in the distribution of the pancreatic duct are pathognomonic for chronic pancreatitis.
31
Autoimmune Pancreatitis
What causes it? Association?
Typical imaging appearance? DDx for this imaging appearance?
Treatment? Prognosis?
* Autoimmune pancreatitis is caused by an inflammatory lymphoplasmacytic infiltrate. It is associated with Sjögren syndrome and causes elevated serum Igg-4 levels.
* The typical imaging appearance of autoimmune pancreatitis is diffuse “sausage-shaped” enlargement of the entire pancreas; however, a focal or segmental form may mimic a pancreatic mass.
* The differential diagnosis for this appearance would include pancreatic lymphoma, less likely pancreatic adenocarcinoma as there is no ductal dilation.
* Treatment is with steroids, which can lead to a complete resolution.
32
Groove (Paraduodenal) Pancreatitis
What is it?
Affected population?
Histopathologic hallmark?
Downstream effects?
Imaging findings?
Main DDx?
* Groove pancreatitis is an uncommon form of focal pancreatitis of the groove between the head of the pancreas, duodenum, and common bile duct. Groove pancreatitis usually affects young men who are heavy drinkers.
* The histopathologic hallmark is fibrosis in the pancreaticoduodenal groove. Chronic inflammation of the duodenum can cause varying levels of duodenal stenosis or cystic change of the duodenal wall.
* Imaging reflects these findings, with duodenal thickening and cystic change often apparent. The cystic change is best appreciated on MR
* The main differential consideration is adenocarcinoma of the head of the pancreas.
