Case Report

Submitted by: Lucila Martinez CC4

Date accepted: August 29th 2007

Radiological Category: Principal Modality (1):

Principal Modality (2):

Faculty reviewer: Sandra A. A. Oldham, MD

Gastrointestinal

None

CT

Case History

A 19 year old male who presents with abdominal pain and leukocytosis s/p gun shot wound on July 13th, 2007 and multiple abdominal surgeries. Otherwise, patient has no other medical problems.

Case History

Several CT images are provided.

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Radiological Presentations

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Radiological Presentations

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Radiological Presentations

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Radiological Presentations

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Radiological Presentations

• Pancreatic Pseudocyst

• Pancreatic Seroma

• Pancreatic Hemorrhage

•Pancreatic Cystic Neoplasia

Which one of the following is your choice for the appropriate diagnosis?

Test Your Diagnosis

A round, smooth, thin walled, homogenous collection of fluid that measures 4.3 x 3.2 cm located in the distal pancreas. The fluid measures 8.2 HU on 7/23 and 19 HU on 8/4. There are no septae in the cyst. The walls do not enhance with contrast. The head and body of the pancreas are normal in appearance. The liver and gallbladder are unremarkable. There is no intrahepatic biliary duct dilation. The visualized loops of bowel appear normal. The right kidney enhances normally and there is no hydronephrosis. The patient is s/p left nephrectomy, splenectomy, and distal pancreatectomy. Aspirated fluid was cloudy and brown in appearance, very rich in amylase (>24,000 U/L) and lipase (>800 U/L).

• Pancreatic pseudocyst

• Post op seroma

• Pancreatic cystic neoplasia

Findings:

Differentials:

Findings and Differentials

The most common cystic lesion in the pancreas is a pseudocyst. A pancreatic pseudocyst is defined as a localized fluid collection that is either located within the pancreas or adjacent to the pancreas and does not have an epithelial lining. The walls of the pseudocyst are formed by adjacent structures such as the stomach, colon and omentum.

They can occur in three specific situations: after acute/chronic pancreatitis, after parenchymal necrosis and following blunt or penetrating trauma. They usually develop 4-6 weeks after the inciting event. Before this it can only be referred to as an acute fluid collection. Most pseudocysts are asymptomatic but patients can present with abdominal pain, or obstruction of nearby structures such as the duodenum and biliary system.

If the clinical history is compatible with a pseudocyst, then the diagnosis can be made with abdominal CT or ultrasound. CT will demonstrate a circular thin walled fluid collection. Fluid aspiration will finalize the diagnosis.

Complications of pseudocysts include infection, hemorrhage, rupture or obstruction. They are usually managed conservatively but can be drained with a catheter or surgically drained by creating an anastomosis with adjacent structure.

Discussion

The differential for a pseudocyst includes cystic neoplasms such as: serous cystadenoma, mucinous cystic neoplasm, intraductal papillary mucinous tumor and solid/papillary epithelial neoplasm (SPEN). Pseudocysts can be differentiated from these lesions by the size and number of the cysts, presence of an irregular wall, septae, central and intramural nodules.

Serous cystadenomas tend to have multiple, small cysts with a central scar with calcifications. Mucinous cystic neoplasms are large, can be uni or multilocular. They may also contain intramural nodules. Intraductal papillary mucinous tumors are characterized by dilation of the ducts and is usually in the head of the pancreas. Solid/papillary epithelial neoplasms tend to be large and can vary from completely cystic to completely solid. They are surrounded by a thick wall.

The fluid aspirated from these lesions can be very helpful to making a diagnosis. A pancreatic pseudocyst will typically be very rich in amylase, where as a mucinous cystic neoplasia will be viscous and contain extracellular mucin.

The age and presenting symptoms also help to narrow the differential. Serous cystadenoma typically occur in women greater than 60 years old who may present with weight loss, whereas intraductal papillary mucinous tumor tends to occur more in men.

Discussion

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Radiological Presentations

Figure 6a.  Serous cystadenoma. (a) Contrast-enhanced CT scan shows a classic serous cystadenoma (arrow) in the head and neck of the pancreas. The lesion has the appearance of a solid mass with numerous small cysts ("honeycomb" effect). The lobulated outlines and the calcified central scar (arrowhead) are typical findings in these tumors.Sahani et al. Cystic Pancreatic Lesions: A Simple Imaging-based Classification System for Guiding Management. RadioGraphics 2005; 25:1471-1484

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Radiological Presentations

Figure 10a.  Mucinous cystadenocarcinoma. Contrast-enhanced CT scans (a obtained at a lower level than b) show a large cystic mass (arrows) with internal septa in the head of the pancreas. The peripheral and septal calcifications (arrowheads) indicate the malignant nature of the lesion Sahani et al. Cystic Pancreatic Lesions: A Simple Imaging-based Classification System for Guiding Management. RadioGraphics 2005; 25:1471-1484

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Radiological Presentations

Figure 14a.  Multiple branch duct type of IPMT. (a) Contrast-enhanced CT scan shows multiple cystic masses (straight arrow) in the pancreatic head and body. Note the dilated pancreatic duct (curved arrow). Kim et al. Imaging Diagnosis of Cystic Pancreatic Lesions: Pseudocyst versus Non-pseudocyst. RadioGraphics 2005; 25:671-685

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Radiological Presentations

Figure 17a.  SPEN in a 32-year-old woman with epigastric pain. (a) Contrast-enhanced CT scan shows a mixed solid and

cystic mass in the pancreatic head (arrows). Kim et al. Imaging Diagnosis of Cystic Pancreatic Lesions: Pseudocyst versus Non-pseudocyst. RadioGraphics 2005; 25:671-685

Pancreatic Pseudocyst

Diagnosis

Kim YH, Saini S, Sahani D, et al. Imaging Diagnosis of Cystic Pancreatic Lesions: Pseudocyst versus Non-pseudocyst. RadioGraphics 2005; 25:671-685

Sahani DV, Kadavigere R, Saokar A, et al. Cystic Pancreatic Lesions: A Simple Imaging-based Classification System for Guiding Management. RadioGraphics 2005; 25:1471-1484

Howell DA, Shah RJ, Lawrence C. Diagnosis and management of pseudocysts of the pancreas. Uptodate Online Version 15.2

Steer, Michael. Cystic lesions of the pancreas. Uptodate Online Version 15.2

Sawyer, Michael. Pancreatic Pseudocysts. http://www.emedicine.com/radio/topic576.htm

References