Intraductal papillary mucinous neoplasm
Encyclopedia
Intraductal papillary mucinous neoplasm (IPMN) is a type of tumor (neoplasm) that grows within the pancreatic ducts (intraductal) and is characterized by the production of thick fluid by the tumor cells (mucinous). Intraductal papillary mucinous neoplasms are important because if they are left untreated some of them progress to invasive cancer (transform from a benign tumor to a malignant tumor). Just as colon polyps can develop into colon cancer if left untreated, so too do some intraductal papillary mucinous neoplasms progress into an invasive pancreatic cancer
. Intraductal papillary mucinous neoplasms therefore represent an opportunity to treat a pancreatic tumor before it develops into an aggressive, hard-to-treat cancer.
Once a doctor has reason to believe that a patient may have an intraductal papillary mucinous neoplasm, he or she can confirm that suspicion using one of a number of imaging techniques. These include computerized tomography (CT), endoscopic ultrasound (EUS), and magnetic resonance cholangiopancreatography (MRCP). These tests will reveal dilatation of the pancreatic duct or one of the branches of the pancreatic duct. In some cases a fine needle aspiration (FNA) biopsy can be obtained to confirm the diagnosis. Fine needle aspiration biopsy can be performed through an endoscope at the time of endoscopic ultrasound, or it can be performed through the skin using a needle guided by ultrasound or CT scanning.
IPMN forms cyst
s (small cavities or spaces) in the pancreas. These cysts are visible in CT scans (X-ray computed tomography). However, many pancreatic cysts are benign (see Pancreatic disease
).
A growing number of patients are now being diagnosed before they develop symptoms (asymptomatic patients). In these cases, the lesion in the pancreas is discovered accidentally (by chance) when the patient is being scanned (x-rayed) for another reason. There are examples of patients who had a CT scan because they were in a car accident and the CT scan happened to include the pancreas and it revealed an unsuspected IPMN.
Scientists at the Sol Goldman Pancreatic Cancer Research Center at Johns Hopkins reported in the July 20 issue of Science Translational Medicine that they have developed a gene-based test that can be used to distinguish harmless from precancerous pancreatic cysts. The test may eventually help patients with harmless cysts avoid needless surgery. Bert Vogelstein
and his colleagues discovered that almost all of the precancerous cysts (intraductal papillary mucinous neoplasms) of the pancreas have mutations in the GNAS and/or the GNAS gene. The researchers then tested a total of 132 intraductal papillary mucinous neoplasms for mutations in KRAS and GNAS. Nearly all (127) had mutations in GNAS, KRAS or both. Next, the investigators tested harmless cysts such as serous cystadenomas, and the harmless cysts did not have GNAS or KRAS mutations. Larger numbers of patients must be studied before the gene-based test can be widely offered.
), removal of the body and tail of the pancreas (a distal pancreatectomy), or rarely removal of the entire pancreas (a total pancreatectomy). In selected cases the surgery can be performed using minimally invasive techniques such as laparoscopy
.
Pancreatic cancer
Pancreatic cancer refers to a malignant neoplasm of the pancreas. The most common type of pancreatic cancer, accounting for 95% of these tumors is adenocarcinoma, which arises within the exocrine component of the pancreas. A minority arises from the islet cells and is classified as a...
. Intraductal papillary mucinous neoplasms therefore represent an opportunity to treat a pancreatic tumor before it develops into an aggressive, hard-to-treat cancer.
History
At 1982, IPMN was reported as "mucin-producting tumor" by Kazuhiko Ohashi of Japanese Foundation for Cancer Research.Classification
Pathologists classify intraductal papillary mucinous neoplasms (IPMNs) into two broad groups - those that are associated with an invasive cancer and those that are not associated with an invasive cancer. This separation has critical prognostic significance. Patients with a surgically resected intraductal papillary mucinous neoplasm without an associated invasive cancer have an excellent prognosis (>95% will be cured), while patients with a surgically resected intraductal papillary mucinous neoplasm with an associated invasive cancer have a worse prognosis. Intraductal papillary mucinous neoplasms without an associated invasive cancer can be further subcategorized into three groups. They are IPMN with low-grade dysplasia, IPMN with moderate dysplasia, and IPMN with high-grade dysplasia. This categorization is less important than the separation of IPMNs with an associated cancer from IPMNs without an associated invasive cancer, but this categorization is useful as IPMNs are believed to progress from low-grade dysplasia to moderate dysplasia to high-grade dysplasia to an IPMN with an associated invasive cancer.Diagnosis
Intraductal papillary mucinous neoplasms can come to clinical attention in a variety of different ways. The most common symptoms include abdominal pain, nausea and vomiting. The most common signs patients have when they come to medical attention include jaundice (a yellowing of the skin and eyes caused by obstruction of the bile duct), weight loss, and acute pancreatitis. These signs and symptoms are not specific for an intraductal papillary mucinous neoplasm, making it more difficult to establish a diagnosis. Doctors will therefore often order additional tests.Once a doctor has reason to believe that a patient may have an intraductal papillary mucinous neoplasm, he or she can confirm that suspicion using one of a number of imaging techniques. These include computerized tomography (CT), endoscopic ultrasound (EUS), and magnetic resonance cholangiopancreatography (MRCP). These tests will reveal dilatation of the pancreatic duct or one of the branches of the pancreatic duct. In some cases a fine needle aspiration (FNA) biopsy can be obtained to confirm the diagnosis. Fine needle aspiration biopsy can be performed through an endoscope at the time of endoscopic ultrasound, or it can be performed through the skin using a needle guided by ultrasound or CT scanning.
IPMN forms cyst
Cyst
A cyst is a closed sac, having a distinct membrane and division on the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst could go away on its own or may have to be removed through surgery.- Locations :* Acne...
s (small cavities or spaces) in the pancreas. These cysts are visible in CT scans (X-ray computed tomography). However, many pancreatic cysts are benign (see Pancreatic disease
Pancreatic disease
-Pancreatitis:Pancreatitis is inflammation of the pancreas. There are two forms of pancreatitis, which are different in causes and symptoms, and require different treatment:...
).
A growing number of patients are now being diagnosed before they develop symptoms (asymptomatic patients). In these cases, the lesion in the pancreas is discovered accidentally (by chance) when the patient is being scanned (x-rayed) for another reason. There are examples of patients who had a CT scan because they were in a car accident and the CT scan happened to include the pancreas and it revealed an unsuspected IPMN.
Scientists at the Sol Goldman Pancreatic Cancer Research Center at Johns Hopkins reported in the July 20 issue of Science Translational Medicine that they have developed a gene-based test that can be used to distinguish harmless from precancerous pancreatic cysts. The test may eventually help patients with harmless cysts avoid needless surgery. Bert Vogelstein
Bert Vogelstein
Bert Vogelstein is a Howard Hughes Medical Institute investigator at The Johns Hopkins University. He clarified the role of the gene p53, which repairs DNA in dividing cells and destroys the cell if its DNA cannot be repaired. Damaged p53 is responsible for half of all cancers...
and his colleagues discovered that almost all of the precancerous cysts (intraductal papillary mucinous neoplasms) of the pancreas have mutations in the GNAS and/or the GNAS gene. The researchers then tested a total of 132 intraductal papillary mucinous neoplasms for mutations in KRAS and GNAS. Nearly all (127) had mutations in GNAS, KRAS or both. Next, the investigators tested harmless cysts such as serous cystadenomas, and the harmless cysts did not have GNAS or KRAS mutations. Larger numbers of patients must be studied before the gene-based test can be widely offered.
Treatment
The treatment of choice on most occasions is surgery. Surgery can include the removal of the head of the pancreas (a pancreaticoduodenectomyPancreaticoduodenectomy
A pancreaticoduodenectomy, pancreatoduodenectomy, Whipple procedure, or Kausch-Whipple procedure, is a major surgical operation involving the pancreas, duodenum, and other organs...
), removal of the body and tail of the pancreas (a distal pancreatectomy), or rarely removal of the entire pancreas (a total pancreatectomy). In selected cases the surgery can be performed using minimally invasive techniques such as laparoscopy
Laparoscopy
Laparoscopy is an operation performed in the abdomen or pelvis through small incisions with the aid of a camera...
.
See also
- Pancreatic mucinous cystic neoplasmPancreatic mucinous cystic neoplasmPancreatic mucinous cystic neoplasm, also mucinous cystic neoplasm of the pancreas and mucinous cystic tumour, is a grouping of cystic neoplasms that arise from the pancreas...
- Pancreatic serous cystadenomaPancreatic serous cystadenomaPancreatic serous cystadenoma, also known as serous cystadenoma of the pancreas and serous microcystic adenoma, a benign tumour of pancreas...
- Solid pseudopapillary neoplasm