Pancreas pathology

Fatty Infiltration

The pancreas will be bulky and echogenic.
This example shows sparing of the uncinate process which has different embryologic origins.

Ultrasound image- Fatty infiltration of the pancreas with focal sparing of the uncinate process.

In the ultrasound image you can see no mass effect or compression of the CBD. A progress u/s to confirm or, if in doubt, a double contrast CT can help confirm this finding.

Fatty Sparing of the Uncinate Process.

Ultrasound image- Fatty Sparing of the Uncinate Process.

Ultrasound image- A hypoechoic uncinate process may be reported as a false positive of a pancreatic head mass.
Look for a smooth continuous outline of the pancreatic head and no disruption to the gastroduodenal artery or common bile duct.

To learn about pancreatic embryology

Pancreatic Simple Cyst

Ultrasound of a simple cyst in the body of the pancreas. If a connection is seen to the pancreatic duct, this may represent a choledochal cyst.

Ultrasound image- Simple cyst in the pancreatic body/tail.

Ultrasound image- Use doppler to confirm the absence of flow when differentiating between a cyst / vein / or tumor.

Ultrasound image – Demonstrates a well defined anechoic cyst (arrow) adjacent to the distal CBD within the pancreatic head. 

Pancreatic Cyst – ultrasound image.

Pancreatic Cyst- post contrast CT same patient confirming it is a cyst

Lymph Node

Ultrasound image- Sagittal view of the lymph node at the pancreatic neck.

A lymph node impressing on the pancreatic neck. Confirmed with CT and a 6/12 follow up ultrasound.

Patients have an ultrasound if they experience painless obstructive jaundice, which is caused by compression or ingrowth of the distal common bile duct.

The level of obstruction should be determined.
In patients with a pancreatic head tumor, typically dilatation of the common bile duct and pancreatic duct (double duct sign) is seen, which is very suggestive for a mass in the pancreatic head, even in the absence of a visible mass.
The tumor itself usually presents as a hypoechoic mass (seen below).

Dilated Pancreatic Duct

  • A dilated pancreatic duct may be secondary to pancreatitis, chelodocholithiasis or history of ERCP.

Ultrasound image- A dilated Pancreatic Duct secondary to a past history of obstructive pancreatits.

Ultrasound image- A single calculus within the pancreatic duct.

Ultrasound image- Several calculi seen to be mobile within the dilated pancreatic duct.

Ultrasound image- A small calculus (red arrow) within a non-dilated pancreatic duct.

Pancreatic Pseudocyst

The most common cystic lesion associated with the pancreas:

  • Ususally secondary to trauma or pancreatitis.
  • Results from disruption and leakage of enzymes from the pancreatic ducts.
  • The intense reultant inflammatory reaction results in encapsulation forming a cyst.
  • Not called a pseudacyst until this encapsulation happens. (It may merely be free fluid prior to this)
  • Most commonly lies towards the tail at the lesser curvature of the stomach but may lie anywhere over the pancreas.
  • Often resolve spontaneously.

Differential diagnoses include:

  • Abscess
  • Serosanguinous fluid exudate from regional inflammation (not encapsulated).
  • Haematoma (post surgical or splenic injury)
  • Necrosis of the pancreas

Ultrasound image- A complex fluid area in the left upper quadrant of the abdomen may represent stomach contents or pathology such as a pancreatic pseudocyst.

See next image…..

Ultrasound image- By giving the patient an oral water-load (3 cups of water is suffiicient) the stomach can be clearly differentiated from the cyst.

Initially, the water will be echogenic (as seen here) due to the microbubbles often present in tap water. After several minutes the water will become anechoic.

Ultrasound image- A sagittal view of a large pancreatic pseudocyst arising from the pancreatic tail.

Ultrasound image- A pancreatic pseudocyst located at the head of the pancreas, secondary to pancreatitis.

Calcific Pancreatitis

Ultrasound image- Chronic recurrent pancreatitis results in fibrosis which may progress to calcification within the parenchyma.

A CT scan of the same patient

WHO Classification of Pancreatic Tumours (1)

I. Benign

a. Serous cystadenoma
b. Mucinous cystadenoma
c. Intraductal papillary mucinous adenoma
d. Mature cystic teratoma

II. Borderline

a. Mucinous cystic tumor with moderate dysplasia
b. Intraductal papillary mucinous neoplasm (IPMN)
c. Solid-pseudopapillary tumor

III. Malignant

a. Ductal adenocarcinoma
b. Osteoclast-like giant cell tumor
c. Serous cystadenocarcinoma
d. Mucinous cystadenocarcinoma
e. Intraductal papillary mucinous carcinoma
f. Acinar cell carcinoma
g. Pancreatoblastoma
h. Solid-pseudopapillary carcinoma
i. Miscellaneous carcinoma

Pancreatic Adenocarcinoma

  • Poor prognosis due to the often late presentation. So, early detection through careful scanning of the pancreas is vital.

Ultrasound image- Vascularity continuous with the pancreas confirms that the lesion is not merely abutting the pancreas.

Ultrasound image of a well circumbscribed lesion in the pancreatic head.

The differential diagnosis of a pancreatic head tumor includes carcinoma, focal pancreatitis, lymphoma and metastasic disease.
Sometimes it is difficult to differentiate between a pancreatic head tumor and focal pancreatitis in the pancreatic head.

Longitudinal ultrasound image of the pancreas. 
A large irregular hypoechoic mass is seen occupying the head and neck.

Note the ill-defined margins and extension into the pancreatic parenchyma.  

Transverse B-mode and colour Doppler image of the pancreas. 

The absence of vascularity within a mass does not exclude neoplasia.

Extensive metastasis were noted in the liver. Biopsy revealed a poorly differentiated adenocarcinoma. 

Serous Cystadenoma

Transverse ultrasound image of the pancreas. 

A well-defined lobulated cystic lesion is seen containing septations and intramural wall thickening. 

Colour Doppler image – no discernible internal vascularity is seen within the septations or wall of the lesion. 

Transverse ultrasound image demonstrating the lesion is separate from the CBD with no extrinsic compression.

Longitudinal ultrasound image of the pancreas. 

Diagnosed as a serous cystadenoma on MRI follow-up. 

Islet Cell Tumour

Transverse ultrasound image of a small low-grade neuroendocrine tumour within the pancreatic body.

B-mode and colour Doppler image. 

Findings were a well-circumscribed rounded hypoechoic lesion with peripheral vascularity in a fatty pancreas. 

Lymphoma

A difficult case example of a large body habitus with obscuring views.  
Transverse ultrasound image of the pancreas demonstrating a large infiltrating hypoechoic lymphoma involving the pancreatic body and tail. 

Longitudinal ultrasound image of the pancreas. 

The linear hyperechoic foci within the mass is enhancement from a tortuous splenic artery  encased within the mass. 

Ultrasound image – para-aortic lymphadenopathy secondary to the advanced lymphoma.

Ultrasound image – left groin lymphadenopathy, also seen in both axilla. 

References

  1.  http://pancreas.org/pancreas/pathology-malignant/
  2. Abdominal Ultrasound How Why and When 2010 3rd Edition Dr Jane A Bates
  3. Rosewicz S, Wiedenmann B. Pancreatic carcinoma. Lancet 1997;349:485-9
  4. Karlson BM, Ekbom A, Lindgren PG, Kalskogg V, Rastad J. Abdominal US for diagnosis of pancreatic tumor: prospective cohort analysis. Radiology 1999;213:107-11.
  5. Gulik TM van, Moojen TM, Geenen R van, Rauws EA, Obertop H, Gouma DJ. Differential diagnosis of focal pancreatitis and pancreatic cancer. Ann Oncol 1999;10(Suppl 4):85-8.
  6. Rumack CM, Wilson SR, Charboneau JW. Diagnostic Ultrasound, 2nd ed. St.Louis: Mosby, 1998:175-200