Online Quiz

CASE 5 ( Closed )

History :
48 yrs male presented with abdominal pain for 1 month.

Question:

Your diagnosis / differentials.

Please see the answer below.

ANSWER

FINDINGS:






























DIAGNOSIS- Groove pancreatitis

TEACHING POINTS:
The sheetlikecrescentic soft tissue found in the pancreaticoduodenal groove is typically mildly hypointense on T1-weighted images and variable in signal intensity on T2-weighted images.The T2 intensity of this soft tissue can vary widely depending on the acuity of the process. In the acute phase, the tissue tends to be more T2hyperintense because of edema and fluid and becomes progressively more hypointense over time because of the accumulation of a fibrotic component. Involvement of the pancreas is well visualized on MRI in the segmental form, with progressive loss of T1 signal intensity in the pancreatic head as a result of parenchymal atrophy and fibrosis.

The medial duodenal wall is involved in both the pure and segmental forms of groove pancreatitis, with duodenal wall thickening and multiple T2hyperintense cysts in both the duodenal wall and pancreaticoduodenal groove. The medial duodenal wall can appear focally as T2hyperintense and hyperenhancing at the site of abnormality.

DISCUSSION / GENERAL CONSIDERATIONS:

Groove pancreatitis, a rare form ofchronic pancreatitis affecting the"groove" between the superior aspectof the pancreatic head, the duodenum,and the common bile duct, was firstdescribed by Becker in 1973.

The pancreaticoduodenal groove is asmall theoretic space bordered by the pancreatichead (medial), second portion ofthe duodenum (lateral), third portion ofthe duodenum and inferior vena cava (posterior),and duodenal bulb (superior). Thedistal common bile duct, main pancreaticduct, accessory pancreatic duct, major papilla,and minor papilla are all found withinthis space, within either the pancreatic heador duodenum.

The exact underlying cause of groove pancreatitisis unclear, although a number of differenttheories exist: functional obstructionof the minor papilla or duct of Santorini, increasinglyviscous pancreatic secretions asa result of alcohol use or smoking, Brunnergland hyperplasia resulting in stasis of pancreaticsecretions in the dorsal pancreas, heterotopicpancreas in the duodenum, and pepticulcer disease have all been suggested aspotential contributing factors. However,a long history of alcohol abuse is thoughtto be the strongest associationGroove pancreatitis has traditionally beendivided into two forms. The pure form affectsonly the pancreaticoduodenal groove (i.e.,between the pancreatic head and duodenum),whereas the segmental form is centered inthe pancreaticoduodenal groove but also extendsmedially into the pancreatic head. Thedemarcation between these two forms ofgroove pancreatitis is not always completelyclear. Some cases of pure groove pancreatitiscan result in progressive narrowing of thepancreatic duct and, subsequently, lead to diffusechanges of chronic pancreatitis in the entiretyof the pancreatic parenchyma.

CLINICAL FEATURES:

The clinical presentation of groove pancreatitiscan vary greatly in its acuity, and althoughsome patients can have a presentationsimilar to that of acute pancreatitis, others canhave a more chronic disease course. In theacute setting, patients often present with severeabdominal pain, nausea, vomiting, and,in rare cases, acute gastric outlet obstruction.Alternatively, patients with a chronic presentationoften have evidence of jaundice (as a resultof distal common bile duct narrowing andstrictures) and chronic weight loss.

Biochemical markers areonly of limited use: Pancreatic enzymes areoften normal or only minimally elevated,and tumor markers (e.g., carcinoembryonicantigen and CA-19-9) are usually negative. Bilirubin levels can be elevated if thecommon bile duct is obstructed.

IMAGING FINDINGS:

The MDCT findings of groove pancreatitisvary between the segmental and pure formsof the process.

In the pure form, the appearancecan range from ill-defined fat strandingand inflammatory change in the groove betweenthe pancreatic head and duodenum, tofrank soft tissue in the groove. Notably, this soft tissue often has a"sheetlike" curvilinear crescentic shape thatis best appreciated on coronal multiplanar reformatted images. If multiphaseimaging is performed, this soft tissuetends to show increasing delayed enhancementas a result of a significant fibrotic component.It is not rare to appreciate thickeningof the medial duodenal wall (particularlyon the coronal images), and small cysts are acommon feature either within the thickenedduodenal wall or the pancreaticoduodenal groove itself.

The segmental form can be much more difficultto appreciate, because involvement of thegroove is often obscured by masslike enlargementof the pancreatic head. The segmentalform of groove pancreatitis is very commonlyconfused for a pancreatic head mass, and differentiatingthe two entities can be nearly impossible on the basis of imaging.

Regardless of the specific form of groovepancreatitis, the diffuse retroperitoneal inflammatorychange seen in acute edematouspancreatitis is usually absent with groove pancreatitis. It is rare to visualize fluidin the pararenal spaces or surrounding thepancreas, and diffuse inflammatory change is usually minimal.

Notably, in bothforms, the common bile duct can appear attenuatedand narrowed, a feature often bestappreciated on the coronal multiplanar reformats.In most cases, this narrowing is relativelysmooth, tapered, and regular, without evidenceof "shouldering," irregularity, or abruptmargins. The pancreatic duct can also be narrowedtoward the downstream pancreatichead, typically in a smooth gradual fashion. Ina more chronic setting, changes in the pancreaticparenchyma resembling those of traditionalchronic pancreatitis can develop secondaryto this progressive narrowing and fibrosis ofthe downstream pancreatic duct, includingpancreatic calcifications, ductal dilatation, andductal beading or irregularity.

Findings on MRI largely mirror thoseseen on CT:

MRCP can nicely reveal abnormalities ofthe distal common bile duct and downstreampancreatic duct, both of which tend to be narrowednear the ampulla. The presence of anabnormality in the groove can be surmisedby evaluating the distance between the ampullaand the duodenal lumen, which is typicallywidened in cases of groove pancreatitis(as a result of soft tissue in the groove andthickening of the duodenal wall). Finally, asa result of narrowing at the ampulla and stricturesof the distal common bile duct, a dilated"banana-shaped" gallbladder has been describedas an ancillary finding.

TREATMENT:

The treatment isusually supportive (similar to cases of conventionalacute edematous pancreatitis), typicallycomprising a combination of fasting, parenteral nutrition, bed rest, and cessation of smoking oralcohol use [5]. Intervention is usually not attemptedin the absence of acute complications,such as biliary obstruction or severe gastricoutlet obstruction, as a result of duodenal edema,wall thickening, fibrosis, and stricture. Inthe chronic setting, some patients may requiredefinitive surgery as a result of severe pancreaticinsufficiency, weight loss, or intractable painsymptoms, and this subset of patients usuallyundergoes classic pancreaticoduodenectomy (Whipple procedure),although endoscopic drainage of the minorpapilla has also been shown to be effectivein some patients.

DIFFERENTIAL DIAGNOSIS:

  • Pancreatic Adenocarcinoma.
  • Duodenal Adenocarcinoma.
  • Ampullary Carcinomas.
  • Duodenal Gastrointestinal Stromal Tumorand Carcinoid.
  • Paraduodenal Pancreatitis.

REFERENCES:

  1. Groove Pancreatitis: Spectrum of Imaging Findings and Radiology- Pathology Correlation- Siva P. Raman1Safia N. Salaria2Ralph H. Hruban2 Elliot K. Fishman1.
  2. Blasbalg R, Baroni RH, Costa DN, et al. MRI featuresof groove pancreatitis. AJR2007; 189:73–80.
  3. Balakrishnan V, Chatni S, Radhakirshnan L, etal. Groove pancreatitis: a case report and reviewof the literature. JOP2007; 8:592–597.
  4. Triantopoulou C, Dervenis C, Giannakou N, et al.Groove pancreatitis: a diagnostic challenge. EurRadiol2009; 19:1736–1743.
  5. Tezuka K, Makino TY, Hirai I, Kimura W.Groove pancreatitis. Dig Surg2010; 27:149–152.
  6. Manzelli A, Petrou A, Lazzaro A, et al. Groovepancreatitis: a mini-series report and review ofthe literature. JOP2011; 12:230–233.
  7. Kim JD, Han YS, Choi DL. Characteristicclinical and pathologic features for preoperativediagnosed groove pancreatitis. J Korean SurgSoc2011; 80:342–347.
  8. LevenickJM, Gordon SR, Sutton JE, et al. A comprehensive,case-based review of groove pancreatitis.Pancreas 2009; 38:e169–e175.
  9. Becker V. Bauchspeicheldruse (Inselapperatausgenommen). In: Doerr W, ed. Speziellepathologischeanatomie. Berlin, Germany: Springer-Verlag, 1973.