What is Mucinous Cystic Pancreatic Neoplasms?
Mucinous cystic pancreatic neoplasms (or MCPNs for short) are a type of growth that creates mucus-filled sacs in the pancreas, typically in the middle or tail end of the organ. These are usually harmless but can sometimes become serious if they develop into areas of abnormal cell growth and evolve into invasive cancer. It’s crucial to distinguish MCPNs from other types of pancreatic cysts, including harmless ones like serous cystadenomas as well as pre-cancerous growths like intraductal pancreatic mucinous neoplasms. MCPNs often show no symptoms and are typically discovered during scans for other health reasons. Advances in imaging and endoscopy (looking inside the body using a flexible tube with a camera) have improved the accuracy of identifying MCPNs, enabling doctors to devise the best treatment options. Because of the risk these MCPNs can become malignant (cancerous), all MCPNs should be removed surgically in patients healthy enough for the procedure.
A review of these MCPNs would include understanding where they commonly occur, what causes them, the process of how they form, what they look like under a microscope, how they present clinically, how they are evaluated, and how they are managed. This review would also underscore the importance of a team-based approach in caring for patients with these pancreatic conditions.
What Causes Mucinous Cystic Pancreatic Neoplasms?
The exact cause of MCPNs, a type of benign tumor, isn’t fully understood, but it’s thought that female reproductive hormones might play a role. This theory comes from several observations: MCPNs tends to occur more often in women, the cells lining these tumors have receptors for estrogen and progesterone (two female hormones), and the tumors themselves have a characteristic appearance that resembles ovarian tissue.
There’s also evidence that certain genetic mutations may be involved, especially in cases where MCPNs develops into cancer. The genes that are often mutated in these cases include KRAS, CDKN2A, TP53, and SMAD4.
Risk Factors and Frequency for Mucinous Cystic Pancreatic Neoplasms
Mucinous cystic pancreatic neoplasms, also known as MCPNs, are typically found in middle-aged women. They’re usually discovered when people are around 48 years old. However, a lot of people with MCPNs don’t have any symptoms, so we don’t know exactly how many people have them. Because of better imaging techniques, more and more of these symptom-free pancreatic cysts are being found. In fact, a study in 2015 showed that up to 10% of all CT scans of the abdomen found pancreatic cysts.
MCPNs are the second most common type of pancreatic cyst found, after intraductal papillary mucinous neoplasms. Here are some important details about MCPNs:
- Most of them (93%) are found in either the body or tail of the pancreas and they’re usually found alone.
- They usually measure about 5 cm in size on average.
- Malignant MCPNs (ones that are or may become cancerous) tend to be larger than benign (non-cancerous) ones.
- The vast majority of MCPNs (72%) are benign. Less common are borderline MCPNs (10.5%), in situ carcinoma (5.5%) and invasive carcinoma (12%).
- People who have invasive MCPNs tend to be older, usually about a decade older than those who have benign MCPNs.
Signs and Symptoms of Mucinous Cystic Pancreatic Neoplasms
Most people with MCPN (mucinous cystic neoplasms of the pancreas) don’t show any symptoms. However, some individuals may experience symptoms, with abdominal pain being the most common. Other less common symptoms might include weight loss, a feeling of fullness in the abdomen, loss of appetite, and fatigue. Large MCPNs can press against nearby organs and structures causing discomfort and a feeling of fullness. Rarely, they can block the ducts in the pancreas, resulting in acute pancreatitis.
- Abdominal pain
- Weight loss
- Sensation of abdominal fullness
- Loss of appetite
- Fatigue
During a physical examination, doctors might not find any clear signs of MCPNs. However, if the MCPN is large, they might be able to feel a fullness or vague mass in the upper abdomen. Since MCPNs rarely occur in the head of the pancreas, jaundice, or yellowing of the skin and eyes, is not a common sign.
Testing for Mucinous Cystic Pancreatic Neoplasms
If your doctor suspects you might have an MCPN, which stands for Mucinous Cystic Pancreatic Neoplasm, a kind of growth in your pancreas, they will start by ordering a few tests. These include a complete blood count, a metabolic panel, a serum lipase test, and a CA 19-9 test. The CA 19-9 test checks for a type of protein that may increase in cancer patients.
Once your blood tests are done, your doctor will want some pictures of your pancreas. This is usually done with a very detailed CT scan or an MRI with contrast. Both these tests are good at giving a clear picture of deep inside your body. Doctors can spot an MCPN by looking for a specific kind of lump in your pancreas, usually in the middle or the tail end of the organ. These lumps often have hard areas in them called calcifications and usually don’t connect to anything else in the pancreas. MRI can be particularly useful in telling MCPN apart from another similar condition called an intraductal papillary mucinous neoplasm.
If the imaging tests suggest that the tumor might be cancerous, your doctor might then want a sample of the fluid from the cyst to test. This can usually be done with an endoscope, a thin tube passed through your stomach. Doctors can identify a cancerous MCPN growth by looking at the fluid’s levels of a protein called CEA, the presence of mucin (a type of protein), low glucose levels, and normal amylase levels.
In some cases, your doctor may also want to do a kind of test called a molecular analysis. One molecular marker, KRAS, is very specific for MCPN. If you have this mutation, it’s very likely you have a mucinous cyst.
Treatment Options for Mucinous Cystic Pancreatic Neoplasms
The treatment options for MCPNs, which are various types of growths in the pancreas, depend on several factors. These factors include the size of the growth, whether there are high-risk features, the symptoms the patient is experiencing, and how well the patient’s body can handle surgery.
Different international medical associations have different recommendations for how to manage MCPNs. The American Gastroenterological Association (AGA) and the American College of Gastroenterology recommend closely watching, but not treating, small MCPNs (less than 3 cm in size) that don’t have any high-risk features and aren’t causing symptoms. High-risk features include things like lumps within the cyst, a dilated pancreatic duct, or high levels of a substance called CA 19-9 in the blood, which can indicate cancer. The AGA suggests doing an MRI scan a year after diagnosis, then once every two years for five years.
However, other guidelines from the 2017 International consensus recommend surgery for all MCPNs, regardless of size or other features. This recommendation takes into account that the chances of a small MCPN becoming malignant seem to be almost zero, especially when CA 19-9 levels are normal. Therefore, some medical professionals feel that watchful waiting is a reasonable strategy in these cases.
For MCPNs that have high-risk features or are causing symptoms, surgery is usually the recommended treatment. The specific type of surgery depends on the size and location of the tumor within the pancreas. For most growths located in the body or the tail of the pancreas, either a distal pancreatectomy (removal of the tail of the pancreas) or a more extensive distal subtotal pancreatectomy might be done. Surgeons may try to preserve the spleen, unless there are signs that the disease has spread. In cases with high-risk features, a distal pancreatectomy with removal of the spleen and nearby lymph nodes might be recommended. If the tumor is in the head of the pancreas, a pancreaticoduodenectomy (removal of the head of the pancreas) may be required.
What else can Mucinous Cystic Pancreatic Neoplasms be?
When a doctor is trying to diagnose a cystic tumor in the pancreas, there are several conditions they may consider. These include:
- Intraductal papillary mucinous neoplasm – a type of tumor growing inside the pancreatic ducts
- Pancreatic pseudocyst – a type of fluid-filled sac that can form in the pancreas
- Serous cystadenoma – a benign (not cancerous) tumor that can occur in the pancreas
- Pancreatic ductal adenocarcinoma – a common type of pancreatic cancer that starts in the ducts of the pancreas
- Pancreatic neuroendocrine tumor – a less common type of pancreatic cancer that starts in the hormone-producing cells of the pancreas
What to expect with Mucinous Cystic Pancreatic Neoplasms
The final diagnosis determines what the future holds for patients with MCPNs, a type of cyst in the pancreas. Patients with non-invasive MCPNs (which have not spread outside the pancreas) usually have a very favorable prognosis, with all patients surviving 5 years past their diagnosis. Interestingly, there seems to be no noticeable difference in survival rates between low-grade and high-grade non-invasive conditions. The low-grade and high-grade refer to how abnormal the cells are. On the other hand, patients with invasive neoplasms (cysts that have spread outside the pancreas) have a significantly worse prognosis, with only 26% of patients surviving 5 years past their diagnosis.
Poor prognosis (or worse outcomes) are often linked with advanced age, degree of tumor invasion (how far the tumor has spread), and multifocality (presence of multiple tumors).
Possible Complications When Diagnosed with Mucinous Cystic Pancreatic Neoplasms
Complications related to MCPNs are usually due to the measures taken for diagnosis and treatment. For example, endoscopic ultrasound, which is a diagnostic tool, generally has a low complication rate, but serious issues like stomach or small intestine perforation, sudden inflammation of the pancreas, or bleeding might occur.
In treating MCPNs, the most common surgical procedures are distal pancreatectomy or subtotal pancreatectomy. These operations can lead to complications such as leakage from the cut area of the pancreas creating a fistula, bleeding, damage to nearby organs, and infections arising from removing the spleen. There can also be more general complications tied to long surgeries under general anesthesia, such as a blood clot deep in the veins.
Post-surgery, there might be a possibly frequent issue of pancreatic leaks, identifiable by elevated amylase levels in the pancreatic drainage fluid. The persisting leaks are known as fistulas. Typically, these can heal without further intervention but continuous drainage may be necessary. Some patients might need minimal invasive drainage for small fluid accumulation. In rare cases, the patient might need intensive care for infections and multiple organ failure due to persisting pancreatic leaks. This situation requires prompt surgical action.
The amount of pancreatic tissue removed during surgery can result in postoperative impaired glucose tolerance and diabetes. Infections arising from removing the spleen surgically can be prevented by appropriate vaccination beforehand.
Here’s a summary of the potential complications:
- Stomach or small intestine perforation
- Sudden inflammation of the pancreas
- Bleeding
- Leakage from the cut area of pancreas creating fistula
- Injury to nearby organs
- Infections due to removal of the spleen
- Complications from long surgeries under general anesthesia
- Impaired glucose tolerance and diabetes post-surgery
Preventing Mucinous Cystic Pancreatic Neoplasms
There are no known ways to change personal habits or behaviors to prevent the development of MCPNs, also known as mucinous cystic pancreatic neoplasms, which represent a type of growth in the pancreas.
If the doctor thinks a patient might have MCPN and they display high-risk features, further evaluation for a potential surgical procedure is needed. This is especially the case for growths larger than 3cm and those with features indicating high-risk, as they have a greater chance of developing into a malignant – or cancerous – condition.
Luckily, the outlook for most patients with MCPNs is very good. It’s important to have the condition managed at a medical center that specializes in pancreatic surgery. They can ensure that the diagnosis is accurate and that the patient receives the best treatment possible.
