Introduction:
Intraductal papillary mucinous neoplasms can spread to the surrounding tissues and are invasive. The tumor produces a thick fluid, hence also called a mucin-producing tumor. The cells show changes in size and shape or dysplastic features. They form a fluid-filled cystic space inside the pancreas. IPMN is a mucin-producing papillary growth within the pancreatic duct. Communication with the main pancreatic duct is the most reliable feature in identifying IPMN from other lesions.
What Is Intraductal Papillary Mucinous Neoplasm (IPMN)?
This intraductal papillary tumor is seen during the fifth and sixth decades of life. The tumor appears as a single cyst or multi-cystic lesion separated from others in a compartment fashion. About six percent of patients diagnosed with IPMN have discovered the condition accidentally during other diagnostic procedures. One of the factors causing IPMN in patients is the mutations seen in the pancreatic gene, such as GNAS and KRAS genes. The cysts in the pancreas do not show such mutations in it. The IPMN tumor is classified into various types, depending on the invasion of the tumor to the surrounding pancreatic ducts. They are
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MD-IPMN: This involves the pancreatic duct's main division (MD). There will be dilatation in the main duct and focal or cystic pancreatic duct.
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BD-IPMN: This includes the pancreatic duct's branching division (BD). This is seen equally in both the male and female populations. The branching duct always comes in contact with the main pancreatic duct. Around 40 percent of cysts are randomly distributed within the distal branches. These branching IPMNs are less aggressive and have less chance of becoming malignant.
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Mixed Type IPMN: This involves the pancreatic duct's main and side branching divisions.
The tumor progresses in three stages, with an initial lesion showing adenoma, then a borderline malignancy followed by the intraductal papillary mucinous neoplasm (IPMN), the most malignant form. The common site of occurrence involves four percent in coiled structures, seven percent in the tail of the pancreas, 39 percent in other parts, and 50 percent of cysts seen in the head of the pancreas.
What Are Symptoms Noted in Intraductal Papillary Mucinous Neoplasm?
The patient may show a variety of symptoms. Some of the manifestations are:
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Abdominal pain.
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Nausea and vomiting.
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Weight loss.
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The patient may find sudden high blood sugar values.
What Are the Clinical Features of Various Intraductal Papillary Mucinous Lesions?
Different lesions exhibit different features in the microscopic examination. Some of the lesions showing unique features during the study are as follows:
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Serous Cystadenoma: This is a less malignant lesion. The rate of incidence is less than 0.1 %. It commonly occurs in women. On microscopic examination, the lesion shows a stellate scar with a calcified center.
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Mucinous Cystic Neoplasm (MCN): The incidence rate in MCN is six to fifteen percent. These lesions have the potential risk of turning into malignancy. It is commonly seen among older women between the ages of 40 and 50. The lesion shows a single cyst with a body and tail, and hence, it is called a macro cystic lesion.
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Main-Duct IPMN: It has a high incidence of malignancy. It is equally distributed in males and females. On microscopic examination, the cells show dilated pancreatic duct protruding to the papilla of Vater.
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Branching-Duct IPMN: It has a very low chance of turning into a malignancy. This is also equally distributed among both genders. It is seen as a bunch of grapes connecting to the pancreatic duct.
What Are the Tests Conducted to Confirm Pancreatic Intraductal Papillary Mucinous Cancer?
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Computerized Tomography (CT): A CT scan can diagnose the cyst of the pancreas. These cysts are usually benign.
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Endoscopic Ultrasound: This test helps in diagnosing the dilatation of the pancreatic duct or its corresponding branches of the pancreatic duct. A needle is inserted into the pancreatic duct, and the image is captured.
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Magnetic Resonance Cholangiopancreatography (MRCP): The pancreatic ducts are dilated in MRCP. It helps visualize the communication between local ducts and detect tumor masses in the intraductal areas.
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Fine Needle Aspiration Biopsy: This procedure can be performed together during the endoscopic ultrasound. It is a confirmatory test for the diagnosis.
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Cystic Fluid Analysis (CEA): If the cyst contains less than five ng/mL mucin in it, then it is known to be a pseudocyst or serous cyst. If the mucin content is more than 92 ng/mL, then it is known to be a classic case of IPMN.
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Cytological Study: The cellular study shows a high rate of dysplasia with the cellular arrangement in varying shapes and sizes. The presence of mucin content in the cyst itself is indicative of IPMN or high-grade cancer.
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Molecular Markers: Mutation of genes such as KRAS and GNAS indicates IPMN.
How do Doctors Treat Intraductal Papillary Mucinous Neoplasms?
If an IPMN is deemed low risk, healthcare practitioners may advise close surveillance of the tumor. Many benign IPMNs do not progress to malignancy. However, if individuals have a tumor in the main pancreatic duct, their doctor may prescribe surgery to remove it. Here are several examples:
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Distal Pancreatectomy: The tail and/or body of the pancreas are removed, removing cancers identified in the main ducts located in these parts of the pancreas.
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Total Pancreatectomy: The entire pancreas, gallbladder, common bile duct, sections of the stomach and small intestine, and, most commonly, the spleen are removed.
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Whipple Procedure (Pancreaticoduodenectomy): This surgery may be recommended by the physician if there are tumors in the pancreas head's primary pancreatic ducts. This is the pancreas's broadest point, where it connects to the small intestine. The head of the pancreas, the duodenum (the first part of the small intestine), the gallbladder, a portion of the bile duct, and adjacent lymph nodes are all removed during this surgery.
The post-surgery survival rate is around five years, with 80 to 85 percent devoid of malignancies. The tumor cells do not show any spread to local lymph node tissues. The surgery can be performed in a few cases using laparoscopy or robotic surgery.
Conclusion:
There is no treatment for IPMN, especially in patients with other medical histories. Once the condition is diagnosed, the patient is further assessed, and regular surveillance is done. Only low-risk patients are advised for surgery. The clinical features like large cystic mass, dilation of the ducts, obstruction of ducts, and multifocal lesions turn the IPMN lesion malignant.
