Low-Grade Appendiceal Mucinous Neoplasms (LAMNs)

Low-Grade Appendiceal Mucinous Neoplasms (LAMNs)


A low-grade appendiceal mucinous neoplasm (LAMN) is a rare tumor of the appendix. LAMNs are often found during treatment for something else. For example, they’re found after people have their appendix removed for appendicitis. They’re also found during imaging tests you had for another health condition.

If the LAMN is only in the inner lining of the appendix, known as “Tis LAMN,” an appendectomy (A-pen-DEK-toh-mee) is curative. Appendectomy is surgery to remove the appendix. People who have Tis LAMN and have an appendectomy do not need additional monitoring or treatment after surgery.

If the LAMN extends into the deeper layers of the appendix, but no spread can be seen at the time of diagnosis, almost everyone (more than 9 out of 10 people) can be cured with an appendectomy. These types of LAMNs are known as T3 or T4 LAMNs. People with T3 or T4 LAMNs should get regular blood and imaging tests to check if the LAMNs have come back. This is called active surveillance (monitoring).

Active surveillance is a type of treatment. It’s not the same as having no treatment. You will have regular blood and imaging tests to see if T3 or T4 LAMNs have come back after an appendectomy.

How do you make an appointment at MSK if you think you have LAMNs?

Your care experience starts with a single phone call. You can request an appointment online at any time or call 888-990-6291 to make an appointment. Our Care Advisors are available Monday through Friday, to (Eastern time).

What happens when I call?

We’ll put you in touch with one of the healthcare providers from our LAMN clinic. Our Care Advisors will help you with scheduling your appointment and finding the right doctor for you. They also can answer your questions.

If you’re feeling stressed or anxious about your diagnosis, our social workers can help. They’re available even before you meet with one of our doctors. They can support you before, during, and after your treatment.

Are LAMNs cancer?

LAMNs are low-grade tumors that make mucus, leading to a larger appendix. They can progress (turn into) a type of appendiceal cancer called “mucinous adenocarcinoma.” This cancer is also known as “epithelial appendix cancer.” Mucinous adenocarcinoma develops when a LAMN grows past the wall of the appendix and spills mucus in the abdomen. For T3 or T44 LAMNs that have not spread past the appendix, the recommended treatment is appendectomy, followed by active surveillance.

High-grade appendiceal mucinous neoplasms (HAMNs) are similar to LAMNs but look more abnormal under a microscope. They are managed the same way as LAMNs and can co-exist with LAMNs. Some patients have both LAMNs and HAMNs.

It can be hard to get a correct diagnosis of LAMNs. This is because it is difficult to differentiate LAMNs from benign (non-cancerous) appendix tumors or appendiceal cancer. That’s why it’s important to get care from experts in treating this condition.

Our pathologists are among the most experienced at diagnosing LAMNs. A pathologist is a doctor who uses a microscope to make a diagnosis from cell and tissue samples. An accurate diagnosis is important to making sure you get the care that’s right for you.

What are the symptoms of LAMNs?

Many people with LAMNs do not have any symptoms. Other people can have:

  • Pain in the abdomen (belly)
  • Nausea (feeling like throwing up)
  • Vomiting (throwing up)
  • Bloating (swollen belly)

What causes LAMNs?

We do not know what causes LAMNs. MSK researchers are studying why some people get LAMNs.

How are LAMNs treated?

Nearly everyone who has LAMNs without spread can be cured by an appendectomy. An appendectomy (A-pen-DEK-toh-mee) is surgery to remove the appendix.

People with T3 or T4 LAMNs (LAMNs that have spread) should get regular blood and imaging tests to check if the LAMNs have come back. This is called active surveillance (monitoring).

How does active surveillance work?

MSK recommends 10 years of active surveillance after surgery for T3 or T4 LAMNs. During the first 4 years, you will have both a computed tomography (CT) scan and a blood test every year. During the last 6 years, you will get a CT scan and blood test every other year.

The CT scans show us if the LAMNs have come back. We also offer magnetic resonance imaging (MRI) scans for people who prefer them to regular CT scans.

Blood tests, such as a carcinoembryonic antigen (CEA) test, help us look for tumor markers (substances shed by active tumors).

Do active surveillance screenings find LAMNs?

Yes. It’s unlikely we will miss a change if you follow your schedule for active surveillance.

Will active surveillance catch LAMNs early enough?

Yes. We understand you may be worried about LAMNs coming back. Research shows that surgery followed by active surveillance is a safe treatment for people with low-risk tumors like LAMNs.

Your care team monitors your active surveillance results closely. They look for important changes that tell us we need to do more treatment. If LAMNs do come back, surgery with or without chemotherapy can be curative.

Where is MSK’s LAMN clinic?

MSK’s LAMNs clinic is in Manhattan. You will only need to come to our clinic for your CT scans and blood work. If you want, you can review your results with your provider in a telemedicine visit (depending on the state you live in).

If you need surgery for LAMNs, your care team will talk with you about where you can have the procedure. 

Request an Appointment

Call 800-525-2225
Available Monday through Friday, to (Eastern time)