Pancreas divisum
Pancreas divisum is the commonest congenital variant of pancreatic anatomy, present in roughly 5–10% of people. In the overwhelming majority it causes no trouble whatsoever and is simply an incidental finding. In a small minority it contributes to recurrent pancreatitis. The clinical difficulty lies in that gap: the variant is common, the problem is rare, and finding divisum in someone with abdominal pain does not by itself establish that it is the cause.
How it forms
The pancreas develops from two separate buds off the embryonic foregut. The ventral bud gives rise to the uncinate process and part of the head; the dorsal bud gives rise to the remainder of the head, the body and the tail. During the seventh week of development the ventral bud rotates behind the duodenum and fuses with the dorsal bud.
Normally their duct systems fuse as well. The dorsal duct connects with the ventral duct, and the combined drainage is redirected through the ventral duct — which becomes the main pancreatic duct (duct of Wirsung) — emptying into the duodenum at the major papilla alongside the bile duct. The proximal dorsal duct regresses to a small accessory channel (duct of Santorini) draining through the minor papilla.
In pancreas divisum the ducts fail to fuse. The two systems remain separate, and the consequence is a drainage mismatch: the larger dorsal duct, carrying secretions from the body and tail — the bulk of the gland — must drain through the minor papilla, which is a small orifice never designed for that volume. The ventral duct drains only the uncinate process and lower head through the major papilla.
The proposed mechanism of disease follows directly: relative outflow obstruction at the minor papilla raises pressure within the dorsal duct system, and in susceptible individuals this produces pancreatitis. Whether this alone is sufficient is debated, and the current view is that divisum is more likely a contributing factor in people who also carry a genetic predisposition — mutations in CFTR, SPINK1 or PRSS1 — than a cause in its own right. This explains why the great majority of people with divisum never develop pancreatitis.
Symptoms
Most people have none and never know they have it. Where symptoms occur, they take the form of:
- recurrent episodes of acute pancreatitis, characteristically without gallstones or alcohol to account for them
- recurrent upper abdominal pain radiating to the back, sometimes without enzyme elevation
- features of chronic pancreatitis, where repeated attacks have caused established damage
How the diagnosis is made
MRI with MRCP is the investigation of choice, and secretin stimulation improves it considerably by increasing pancreatic secretion and distending the ducts, making the separate drainage visible. The characteristic finding is the dorsal duct crossing the bile duct and draining into the minor papilla, with a short ventral duct.
Endoscopic ultrasound and ERCP also demonstrate the anatomy, ERCP being now largely reserved for cases where treatment is intended rather than for diagnosis alone.
The essential diagnostic discipline is exclusion. Before divisum is accepted as the explanation for recurrent pancreatitis, the common causes must be excluded properly: gallstones and microlithiasis, alcohol, hypertriglyceridaemia, hypercalcaemia, medications, autoimmune pancreatitis, and — importantly in older patients — an obstructing tumour. Genetic testing is appropriate in younger patients with recurrent unexplained pancreatitis, and frequently reveals the real predisposition.
Treatment
No treatment
This is the correct management for the great majority. An incidental finding of pancreas divisum in someone without pancreatitis requires nothing at all — no surveillance, no dietary restriction, no intervention. Saying so clearly prevents a lifetime of unnecessary anxiety about a normal variant.
Endoscopic treatment
For patients with genuinely recurrent acute pancreatitis attributable to divisum after proper exclusion of other causes, minor papilla sphincterotomy with or without temporary stenting aims to improve dorsal duct drainage. Results are best in those with documented recurrent acute pancreatitis; they are considerably less predictable in patients whose only symptom is pain, and expectations should be set accordingly before the procedure. Post-procedure pancreatitis is a recognised complication.
Surgery
Surgical sphincteroplasty of the minor papilla is an option where endoscopic treatment fails or is not technically possible. Where chronic pancreatitis has become established, the operation is chosen according to the pattern of disease — a drainage procedure where the duct is dilated, or resection where disease is localised — as for chronic pancreatitis from any cause.
Recovery
Endoscopic sphincterotomy is usually a day-case or overnight procedure, with a recognised risk of pancreatitis afterwards. Surgical sphincteroplasty involves a hospital stay of several days and recovery over a few weeks.
Follow-up
Patients treated for symptomatic divisum are followed to assess whether attacks have genuinely become less frequent, and monitored for progression to chronic pancreatitis. Those with an identified genetic predisposition are counselled about it, including implications for relatives.
When to seek a specialist opinion
Recurrent pancreatitis without an obvious cause deserves specialist assessment, and pancreas divisum is one of the things to look for. Equally — and this is the more common situation — anyone who has been told incidentally that they have pancreas divisum and has never had pancreatitis should be reassured that this is a normal anatomical variant requiring nothing. Intervention is reserved for those in whom the variant has demonstrably caused disease, and the decision to treat is made individually after the alternatives have been properly excluded.
Common questions
What is pancreas divisum?
A normal variation in how the pancreas formed before birth. The organ develops as two buds that fuse, and their ducts normally join so that most pancreatic juice drains through the larger opening. In pancreas divisum the ducts never joined, so the bulk of the juice drains through the smaller opening instead. It is present in roughly one person in ten.
If one person in ten has it, why do so few have problems?
Because the smaller opening is usually perfectly adequate. The variation only matters in the minority whose opening is too narrow to cope with the volume, causing pressure to build in the duct. This is why finding pancreas divisum on a scan does not by itself explain symptoms — most people with it never know.
Is it inherited?
Not in a simple way, and it is not a disease passed from parent to child. It is a common developmental variation. However, where someone with pancreas divisum has repeated pancreatitis, testing for genetic changes such as those in the CFTR or SPINK1 genes is often worthwhile, because these frequently coexist and may be the real driver.
Did this cause my pancreatitis?
It may have contributed, but it should not be assumed. All the usual causes — gallstones, alcohol, high triglycerides, medication, and an underlying tumour — must be excluded first, because they are far commoner and attributing attacks to pancreas divisum too readily leads to unnecessary procedures.
What does the endoscopic treatment involve?
Cutting the small opening to widen it, sometimes with a temporary stent placed across it, so the pancreatic juice drains freely. It is done through an endoscope with no incisions. Results are better in people with recurrent attacks of pancreatitis than in those with chronic pain alone, and this should be made clear before the decision.
What are the risks of the procedure?
The main one is pancreatitis itself, which is a recognised complication of any procedure on the pancreatic duct and occurs in a meaningful proportion. This is precisely why the procedure is reserved for people with clear, documented attacks rather than offered for vague symptoms.
Will it fix my pain?
If you have had repeated proven attacks of pancreatitis, there is a reasonable chance of improvement. If your problem is chronic abdominal pain without documented pancreatitis, the results are considerably less predictable, and you should be given an honest account of that before proceeding.
Do I need an operation?
Rarely. Surgery to widen the opening is reserved for people in whom the endoscopic approach fails or is not technically possible, and it is uncommon in modern practice.
Related conditions
Other conditions of the pancreas covered on this site:
- Pancreatic ductal adenocarcinoma
- Acute pancreatitis
- Chronic pancreatitis and its complications
- Pancreatic cysts — IPMN and MCN
- Pancreatic neuroendocrine tumours
- Solid pseudopapillary neoplasm and other rare pancreatic tumours
- Periampullary lesions
- Annular pancreas
This page provides general information and does not replace an individual medical consultation. Assessment and treatment are decided for each patient after review of their history, examination and imaging.