Pancreatic duct stone

A pancreatic duct stone, also known as calculus, is a stone embedded within the pancreatic ducts. They typically arise in the setting of chronic pancreatitis.

Terminology

Three terms other than pancreatic stones or calculi have been used to refer to calculi in the pancreatic ducts; primarily this has been pancreatolithiasis, however historically the term pancreolithiasis, was more common. Confusingly the third variant pancreaticolithiasis has also been used although much less so than the other two ^3-5.

Epidemiology

The exact incidence of pancreatic duct stones remains to be fully evaluated. The current literature estimates that up to 50% of patients with chronic pancreatitis may have pancreatic duct stones ¹.

Risk factors

Risk factors for pancreatic duct stones include:

• chronic pancreatitis

• alcohol

• smoking

• autoimmune conditions

Clinical presentation

Patients often present with severe upper abdominal pain that has a colicky nature. It is difficult to diagnose based on symptoms alone as patients often have underlying chronic pancreatitis.

Pathology

In chronic pancreatitis and alcoholism, there is a decrease in pancreatic juice protein, leading to the accumulation of crystallization and calcium carbonate deposition. As a result, there is subsequent stone formation ².

Radiographic features

CT

CT features suggestive of a pancreatic stone may include:

• main duct dilatation secondary to luminal obstruction

• hyperattenuation within the pancreatic duct suggestive of a stone

Other features that may raise suspicion of a potential stone include radiological features of chronic pancreatitis.

MRI

MRI, specifically magnetic resonance cholangiopancreatography (MRCP), features may include:

• hypointense or signal void circumscribed structure in the duct on T2 weighted imaging (may or may not be delineated by hyperintense fluid signal depending on the size of the stone)

• low signal or filling defect distal to suspected stone in the pancreatic duct

• dilated pancreatic duct

Treatment and prognosis

Treatment is typically divided into medical, surgical, or endoscopic. Surgical management involves removing obstructing calculi, decompression of the obstructed ducts, and preservation of pancreatic tissue as well as adjacent organs. Endoscopic management involves clearing the calculi from the duct to relieve the obstruction.