Intraductal papillary mucinous neoplasm (IPMN) is a type of

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

that can occur within the cells of the

pancreatic duct The pancreatic duct, or duct of Wirsung (also, the major pancreatic duct due to the existence of an accessory pancreatic duct), is a duct joining the pancreas to the common bile duct. This supplies it with pancreatic juice from the exocrine pancr ...

. IPMN tumors produce mucus, and this mucus can form pancreatic cysts. Although intraductal papillary mucinous neoplasms are

benign tumor A benign tumor is a mass of cells (tumor) that does not invade neighboring tissue or metastasize (spread throughout the body). Compared to malignant (cancerous) tumors, benign tumors generally have a slower growth rate. Benign tumors have re ...

s, they can progress to pancreatic cancer. As such IPMN is viewed as a

precancerous condition A precancerous condition is a condition, tumor or lesion involving abnormal cells which are associated with an increased risk of developing into cancer. Clinically, precancerous conditions encompass a variety of abnormal tissues with an increased ...

. Once an intraductal papillary mucinous neoplasm has been found, the management options include close monitoring and pre-emptive surgery.

Histology

IPMNs are lined with mucin-secreting columnar epithelium.

Diagnosis

Histopathology of intraductal papillary mucinous neoplasm types

In most cases, IPMNs are diagnosed based on clinical and radiographic criteria. If fluid from the cyst is aspirated, the CEA level is typically elevated. Confirmation of the diagnosis with tissue is rarely necessary. By histopathology, IPMN is characterized on light microscopy by Mucinous epithelial cells, and growth within the

Mucin 5AC Mucin-5AC (MUC-5AC) is a protein that in humans is encoded by the ''MUC5AC'' gene. MUC-5AC is a large gel-forming glycoprotein. In the respiratory tract it protects against infection by binding to inhaled pathogens that are subsequently removed ...

is a useful immunohistochemistry marker. Characteristic genetic alterations are those of

KRAS ''KRAS'' ( Kirsten rat sarcoma virus) is a gene that provides instructions for making a protein called K-Ras, a part of the RAS/MAPK pathway. The protein relays signals from outside the cell to the cell's nucleus. These signals instruct the cel ...

and GNAS. Further subtyping of IPMN can be done as either: *

Gross pathology Gross pathology refers to macroscopic manifestations of disease in organs, tissues, and body cavities. The term is commonly used by anatomical pathologists to refer to diagnostically useful findings made during the gross examination Gross pr ...

: Main duct, branch duct, and mixed duct lesions, which determines surgical management. Main duct lesion is the segmental or diffuse dilatation of main pancreatic duct greater than 5 mm without other causes of obstruction. Meanwhile, branch duct lesion is the pancreatic cyst more than 5 mm that communicates with the main duct. The mixed duct lesions fulfills both criteria above. *By light microscopy and immunohistochemistry: Gastric, intestinal, pancreaticbiliary, and oncocytic.

Treatment

The treatment of choice for main-duct IPMNs is resection due to approximately 50% chance of malignancy. Side-branch IPMNs are occasionally monitored with regular CT or MRIs, but most are eventually resected, with a 30% rate of malignancy in these resected tumors. Indications for surgical resection include obstructive jaundice, an enhancing mural nodule >5 mm, and pancreatic duct dilation (>10 mm). Surgery can include the removal of the head of the pancreas (a

pancreaticoduodenectomy A pancreaticoduodenectomy, also known as a Whipple procedure, is a major surgical operation most often performed to remove cancerous tumours from the head of the pancreas. It is also used for the treatment of pancreatic or duodenal trauma, or ch ...

), removal of the body and tail of the pancreas (a

distal pancreatectomy In medicine, a pancreatectomy is the surgery, surgical removal of all or part of the pancreas. Several types of pancreatectomy exist, including pancreaticoduodenectomy (Whipple procedure), distal pancreatectomy, segmental pancreatectomy, and tot ...

), 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 () is an operation performed in the abdomen or pelvis using small incisions (usually 0.5–1.5 cm) with the aid of a camera. The laparoscope aids diagnosis or therapeutic interventions with a few small cuts in the abdomen.Medlin ...

or robotic surgery. A study using

Surveillance, Epidemiology, and End Results The Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute (NCI) is a source of epidemiologic information on the incidence and survival rates of cancer in the United States. The Program SEER collects and pub ...

Registry (SEER) data suggested that increased lymph node counts harvested during the surgery were associated with better survival in invasive IPMN patients.

Prognosis

Survival 5 years after resection of an IPMN without malignancy is approximately 80%, 85% with malignancy but no lymph node spread and 0% with malignancy spreading to lymph nodes.

Epidemiology

Relative incidence of pancreatic neoplasms

Side branch IPMNs are the most common pancreatic cysts. IPMNs occur more often in men than women, and often occur in the 6th and 7th decade of life.

History

In 1982, IPMN was reported as a "mucin-producing tumor" by Kazuhiko Ohashi of the Japanese Foundation for Cancer Research.

References

External links

{{DEFAULTSORT:Intraductal Papillary Mucinous Neoplasm Gastrointestinal cancer Pancreas disorders Pancreatic cancer