The main surgical conditions that affect the pancreas are pancreatitis, cystic tumours of pancreas (serous cystadenoma, mucinous cyst adenoma/carcinoma, Intraductal mucinous cyst neoplasm (IPMN), solid pseudopaillary tumour of pancreas, pancreatic neuroendocrine tumour (pNET), and pancreatic ductal adenocarcinoma.
Pancreatitis
Pancreatitis is inflammation of the pancreas, which can be either acute or chronic.
Acute pancreatitis presents with acute onset of severe epigastric pain radiating to back, associated with nausea, vomiting and jaundice. Two common causes of acute pancreatitis include gallstones and heavy alcohol consumption. Other causes of pancreatitis include autoimmune pancreatitis (with raised IgG4 levels), drug induced, abdominal trauma, iatrogenic (ERCP), hyperlipidaemia (with raised triglycerides levels), hypercalcaemia (with raised calcium levels), hereditary pancreatitis, pancreatic divisum and pancreatic neoplasms. Acute pancreatitis can be severe in 10% of patients with mortality rate of up to 10-20%.
Chronic pancreatitis occurs when patients have recurrent acute pancreatitis, usually from causes such as alcohol abuse. They often have history of multiple hospital admissions with acute pancreatitis, and subsequently develop scaring of pancreas gland with fibrosis and calcification. These lead to chronic abdominal pain, exocrine failure with inability to digest fat and endocrine failure with a new onset of diabetes. Patients with exocrine pancreatic failure present with weight loss, passing frequent pale and loose bowel motions (steatorrhoea).
Cystic tumour of pancreas
Unlike liver cysts are common and almost always benign, pancreatic cysts are rarely simple cyst. Pancreatic cyst can be secondary to acute pancreatitis (pancreatic pseudocyst), which may need endoscopic or surgical drainage if large > 5cm or symptomatic (causing vomiting, haemorrhage or formation of arterial aneurysm).
Serous cystadenoma – Benign cyst of pancreas associated with multiple microcysts and calcifications, common in elderly women
Mucinous cyst adenoma/carcinoma – Mucin containing pancreatic cyst, common in middle-aged women. It has malignant potential up to 40%
Solid pseudopapillary tumour of pancreas – Often large cystic tumour of pancreas in young women, which can recur locally
Intraductal mucinous cyst neoplasm (IPMN)
IPMN is a common incidental pancreatic cystic lesion, which has three subtypes: main duct (dilated main pancreatic duct, MPD > 5mm without pancreatic ductal obstruction), side-branch (pancreatic cyst joining MPD) or mixed type. This is important entity, which may develop into adenoma with mild or severe dysplasia and into pancreatic adenocarcinoma. The risk of malignant transformation for IPMN is up to 60% in main duct type and up to 20-30% in side-branch duct type. Thus, all suspected patients with IPMN should be referred to HPB surgeon or pancreatologist for further assessment.
Pancreatic Neuroendocrine tumour
Pancreatic neuroendocrine tumors (also known as Islet cell carcinoma) are a type of neuroendocrine tumor found in the pancreas. Only 5 percent of pancreatic tumors arise in the islet cells. Most of these tumours are non-functional (non-hormone producing), but some pancreatic neuroendocrine tumors are functional, which means they produce excess hormones that can lead to a variety of hormone-related symptoms.
Insulinomas produces too much insulin, which can cause low blood sugar, and cause symptoms such as dizziness and light-headedness. Glucagonomas may interfere with the production of glucose in the blood, causing an elevation of blood sugar and diabetes. Rarely, glucaganomas can cause a skin rash when they become advanced. Somatostatinomas disrupts the production of a variety of hormones, leading to diabetes, gallstones, and an inability to digest fats. Gastrinomas increases the production of gastrin, a stomach acid that aids in digestion and can lead to the formation of stomach ulcers. VIPomas disrupts the production of vasoactive intestinal peptide (VIP), which helps control the secretion and absorption of water in the intestines. VIPomas can cause severe diarrhea.
Pancreatic cancer
About 2600 Australians are diagnosed with pancreatic cancer each year with the average age of diagnosis, 72. It is the tenth most common cancer in both men and women in 2014.
The risk factors for pancreatic cancer are advancing age, smoking, obesity, diabetes, chronic pancreatitis, exposure to carcinogens (asbestos, pesticides and dyes) and inherited genetic mutation (e.g. BRCA 1 and BRCA2).
Clinical presentations
Symptoms of pancreatic cancer may depend on the size and the location of tumour and the extent of its spread. A tumour in the head of pancreas can cause painless jaundice (yellowish skin and eye, dark urine, pale stool and itchiness of the skin) due to blockage of bile duct. Other symptoms include upper abdominal pain and back pain. The tumour can obstruct the gastric outlet and cause vomiting. An advanced pancreatic cancer can lead to lethargy, loss of appetite and weight loss. Acute pancreatitis or a new onset of diabetes can be a symptom of pancreatic cancer.
Investigations
Blood tests including full blood count (FBE), urea and electrolytes (U&E), liver function test (LFT), coagulation profile (INR) and lipase for pancreatitis are routinely performed.
Other blood tests such as CA 19.9 (for pancreatic carcinoma), chromogranin A (for pancreatic neuroendocrine tumour) and IgG4 for autoimmune pancreatitis can be performed as required.
Abdominal Ultrasound is useful in determining in presence of gallstones, biliary obstruction and solid or cystic pancreatic lesion.
A triple phase (non-contrast, arterial contrast and portovenous contrast), dynamic CT of abdomen and pelvis is the most important investigation in pancreatic conditions. This determines size, location and nature of pancreatic lesion and its relationship to surrounding structures such as superior mesenteric artery (SMA), superior mesenteric vein (SMV)/Portal vein (PV), bile duct, pancreatic duct. CT scan can also show evidence of lymph nodes spread and metastatic disease (omental nodules, liver metastases, ascites, lung metastases).
MRI/MRCP is performed to further characterise the pancreatic lesion.
Endoscopic ultrasound is a very useful test that can characterise the pancreatic lesion and also allows biopsy of lesion.
ERCP is rarely used as a diagnostic test, but is performed for insertion of biliary stent for jaundice.
