In 667, De Graaf provided a moral description of pancreatic stones. In recent years, due to the increasing incidence of chronic pancreatitis and the advancement of various imaging techniques, the detection rate of pancreatic stones has also shown an upward trend. The reported detection rates of pancreatic lithiasis vary both domestically and internationally. Internationally, the detection rate of pancreatic lithiasis accounts for 30-60% of chronic pancreatitis cases during the same period, while domestically, the detection rate is relatively lower, at around 10%. This discrepancy may be related to the fact that chronic alcoholic pancreatitis is less common than biliary diseases in the country.

bubble_chart Etiology

The exact cause of pancreatic stones remains unclear. However, statistical analysis of extensive data indicates that pancreatic lithiasis is associated with alcohol consumption. Cases where individuals have a long history of heavy drinking are more prone to developing pancreatic stones, with the onset typically occurring between the ages of 30 and 50. On average, these individuals consume a daily alcohol intake, along with 100g of protein and 90g of fat. Imamura reported 45 cases of pancreatic stones, among which 43 had a history of alcohol consumption exceeding 10 years. Additionally, there are reports suggesting a link between pancreatic lithiasis and family history, with over 10 families in Japan reported to have this condition. Other factors such as biliary tract diseases and hyperparathyroidism are also related. Long-term protein deficiency can lead to pancreatic cell degeneration and fibrosis, changes similar to those seen in pancreatic lithiasis.

Long-term alcoholism significantly increases the concentration of proteins in pancreatic juice, leading to protein deposition. The protein plugs precipitated in the pancreatic ducts calcify to form stones. In the blood of both normal individuals and patients with chronic pancreatitis, there is a protein called Pancreatic Stone Protein (PSP). PSP inhibits the precipitation of calcium carbonate by binding and blocking its activity. When factors such as long-term alcoholism or malnutrition reduce the secretion of PSP, the supersaturated calcium carbonate in pancreatic juice is no longer inhibited and crystallizes. These calcium carbonate crystals precipitate on the network structure of shed epithelial cells, mucus membranes, pancreatic enzymes, and non-enzymatic pancreatic ferritin. Due to the high potential activity of these crystal surfaces and the large surface area of the network structure, some metal ions are absorbed and deposited onto the network, forming stones over time. Pancreatic stones contain about 95% calcium carbonate, with the surface layer also containing calcium, chromium, magnesium, etc.

Pancreatic stones can be divided into two types: one is main pancreatic duct stones, and the other is calcified stones in small pancreatic ducts. The former is called true stones, while the latter are pseudo-stones. The size of the stones varies, with larger ones being massive, weighing up to 100-200g, mainly embedded in the pancreatic ducts, while smaller ones are barely recognizable. The shapes of the stones are diverse: oval, spherical, branched, triangular, etc.

Long-term retention of pancreatic stones stimulates the epithelial cells of the pancreatic ducts, causing hypertrophy and hyperplasia, followed by squamous metaplasia. This leads to narrowing and blockage of the pancreatic ducts. In the early stages, there is peripancreatic edema and pancreatic swelling, and in the advanced stage, due to both pancreatic duct blockage and pancreatic fibrosis, the pancreas is significantly damaged, manifesting as total or partial atrophy, collapse, and hardening of the pancreas, with a white cut surface and less hemorrhage. Sometimes, due to pancreatic duct blockage, pancreatic cysts or abscesses may develop. Fibrotic tissue can surround and contract the islets, affecting their function and leading to diabetes. On the basis of squamous metaplasia, cancerous transformation may occur.

The symptoms of pancreatic lithiasis can be divided into early and advanced stage manifestations.

1. Early symptoms

Abdominal pain: This is the most common symptom, varying in severity, mainly due to pancreatic duct obstruction and pancreatic fibrosis. It often manifests as upper abdominal distension and fullness pain. In cases of alcoholic pancreatic lithiasis, it often presents as severe pain with recurrent episodes lasting for a long time. For those with an unknown disease cause, severe pain is less common, mostly presenting as upper abdominal dull pain or aching.

Weight loss and steatorrhea: These are caused by reduced pancreatic exocrine function due to chronic pancreatitis with stones. The condition of steatorrhea varies depending on the extent of pancreatic damage.

Jaundice: About 1/4 of patients may develop jaundice. This is due to the fibrotic, hard pancreatic head compressing the lower end of the common bile duct. Jaundice can be persistent or intermittent, with the latter being more common.

2. Advanced stage symptoms

The advanced stage symptoms of pancreatic lithiasis mainly manifest as complications arising from progressive chronic damage to the pancreas.

bubble_chart Auxiliary Examination

1. Laboratory Tests

Serum GPT, GOT, cholesterol, triglycerides, etc., may show grade I abnormalities. AKP may be elevated in a few patients. To differentiate whether pancreatic cancer coexists, carcinoembryonic antigen (CEA) should be tested. CEA staining in pancreatic cancer tissue shows grade II or higher positivity, with pancreatic duct epithelial cells showing mild to grade II positivity.

2. X-ray Plain Film

Pancreatic lithiasis can display three types on X-ray plain film:

Isolated type: one or more massive stones, mostly in the main pancreatic duct.

Mixed type: on the same X-ray film, foxtail millet-like granular stones and massive stones coexist.

Pancreatic stones are most often found in the head of the pancreas, less in the tail, and moderate in the body. Larger stones cause more severe obstruction of the main pancreatic duct, with most cases accompanied by pancreatic duct obstruction and frequent complications.

3. Ultrasound and CT Examination

The sensitivity of pancreatic stones is over 90%. When combined with CT examination, the positive rate is even higher. CT examination can increase the positive detection rate for pancreatic cancer. When pancreatic lithiasis is complicated by pancreatic cancer, calcification, pseudocysts, pancreatic duct dilation, irregular pancreatic shape, localized pancreatic enlargement, and disappearance of peripancreatic fat can be seen.

4. ERCP

Through endoscopy, in addition to observing changes in the pancreatic duct, the number, size, and location of stones, pancreatic fluid can also be examined to further understand the possibility of malignancy. Pancreatic fluid is tested for CEA; if the CEA activity in pancreatic fluid is <30ng/ml (with plasma CEA <2.5ng/ml), it is negative. If pancreatic fluid CEA >30ng/ml (plasma CEA >2.5ng/ml), it is considered positive. Further examinations such as ultrasound-guided fine-needle aspiration cytology should be conducted. When pancreatic duct intubation is performed (after secretin stimulation), collecting pancreatic fluid to check for cancer cells also has a high positive rate.

bubble_chart Diagnosis

The diagnosis of pancreatic lithiasis is not too difficult. A preliminary judgment can be made based on a history of long-term alcohol abuse, symptoms of abdominal pain, and sometimes varying degrees of diabetes. Definitive diagnosis can then be made through laboratory tests, X-ray plain films, ultrasound, CT, and ERCP examinations.

bubble_chart Treatment Measures

The goal of treating pancreatic lithiasis is to remove stones, relieve obstruction, prevent further destruction of the pancreas, prevent malignancy, and alleviate pain.

Common surgical methods include:

1. Endoscopic stone removal

This method is only used for pancreatic stones without pancreatic duct stenosis. If there is no pancreatic duct stenosis, the sphincter can be incised to remove the stones. When the stones are large, they can be removed after ultrasonic or laser lithotripsy. After ultrasonic lithotripsy, the stones are broken into smaller pieces and can be expelled naturally. If there is a factor of pancreatic duct stenosis, even if the stones are broken and removed, the obstruction factor is not relieved, and stones will form again in the future.

2. Partial pancreatectomy

This refers to cases where stones are confined to the body and tail of the pancreas with multiple stones and severe destruction of that part of the pancreas. After resection of the pancreatic body and tail, if there is no stenosis in the proximal pancreatic duct and it does not affect pancreatic juice drainage, the pancreatic stump can be sutured. If there is a factor of stenosis in the proximal pancreatic duct, the distal pancreatic duct can be anastomosed to the jejunum in an invagination or end-to-side Roux-en-Y manner. Since most of the islet cells are located in the tail and body of the pancreas, excessive resection of the pancreatic body and tail in a diseased pancreas will lead to severe pancreatic endocrine insufficiency. Therefore, more of the pancreatic body and tail should be preserved, and pancreaticojejunostomy can be performed if there is proximal stenosis.

3. Pancreatic duct stones combined with pancreatic cysts

On one hand, the stones are removed, and on the other hand, internal drainage is performed between the cyst and the intestine.

4. Pancreatic parenchymal incision for stone removal

This is suitable for stones in the head and body of the pancreas with multiple pancreatic duct stenoses. For isolated stones in the head and body of the pancreas without proximal stenosis, the fibrotic pancreatic tissue is incised at the stone site to remove the stones, and the incised pancreatic duct and pancreas are properly sutured. However, such cases are rare. Generally, multiple stones in the pancreatic duct are accompanied by multiple stenoses and dilations. To relieve obstruction, sometimes the pancreatic duct is largely or almost completely split open to remove all stones, and the split pancreatic duct is anastomosed side-to-side with the jejunum. Since most of the pancreas is fibrotic, bleeding is not excessive when splitting the pancreatic duct.

5. Whipple procedure

This is suitable for multiple stones in the pancreatic head, destruction of the pancreatic head, or malignancy. Pancreaticoduodenectomy is highly destructive and causes severe physiological disturbances, so its indications should be strictly controlled. To reduce injury, if there are no signs of malignancy, a modified (duodenum-preserving) pancreatic head resection can be performed.

The treatment of pancreatic lithiasis has not yet formed a fixed surgical approach because the size, location, degree of pancreatic duct stenosis, and extent of pancreatic tissue fibrosis vary, making treatment challenging. The specific surgical method to be adopted should be considered from multiple aspects before implementation.

6. Treatment of pancreatic stones complicated by pancreatic cancer

When malignancy is suspected during surgery, a frozen section should be performed. After confirmation, the following treatments are carried out:

If the tumor is confined within the capsule and located in the pancreatic head, pancreaticoduodenectomy is performed. If the lesion is extensive in the pancreas without surrounding metastasis, total pancreatectomy can be performed. Postoperative endocrine and exocrine insufficiency is treated with replacement therapy.

For pancreatic head tumors compressing the lower end of the common bile duct causing jaundice, choledochojejunostomy is performed.

When the tumor cannot be completely resected, intraoperative radiation therapy can be performed.

Stirred pulse catheter infusion of chemotherapy drugs can also be used.

In recent years, some have tried external diathermy treatment with certain efficacy.

bubble_chart Complications

Due to the significant damage to the pancreas caused by pancreatic stones, it is prone to cause a series of complications, such as diabetes, pancreatic cancer, etc. The most common complications are as follows.

1. Benign complications of pancreatic stones: Diabetes is the most common, as well as cardiomyopathy, nephropathy, retinopathy, and occlusive arteriosclerosis caused by diabetes. Sometimes liver disease and peptic ulcers can also occur.

2. Symptoms of pancreatic lesions caused by pancreatic stones affecting surrounding organs: Enlargement or fibrotic induration of the pancreas compresses the common bile duct, splenic vein, or leads to splenic-portal vein thrombosis, resulting in secondary portal hypertension, which can be regional or systemic, depending on the extent of the thrombosis.

3. Malignant complications: The malignant complications of pancreatic stones include those of the pancreas itself and malignant tumors outside the pancreas. The relationship between pancreatic stones and pancreatic cancer is extremely close. Generally, pancreatic stones occur first, followed by pancreatic cancer. Pancreatic cancer is often associated with large stones. About half are located in the head of the pancreas. The incidence of pancreatic cancer varies among reports. European and American literature records it as 3.6-25%, while Japanese reports by Hisao Oguchi indicate 31 cases of pancreatic stones complicated by pancreatic cancer (14.8%). General Japanese reports range from 5.3-10%.