Low grade mucinous neoplasm I (LAMN I)

What is a LAMN I?

A low-grade mucinous neoplasm (LAMN I) is a growth found in your appendix. We use this term when the growth is very early and has not spread anywhere.

What causes LAMN I?

The cause of it is unknown but like any growths, they can develop in people who lead healthy lifestyles. There is no evidence that the growth can be transmitted through families. It is not inherited.

Signs and symptoms

Most low-grade mucinous neoplasms are found unexpectedly when patients have had their appendix removed for appendicitis.

How is it diagnosed?

Patients can often present with appendicitis and require an appendicectomy. Others have discomfort and are investigated with an ultrasound or CT scan and the appendix can appear enlarged (this is called a mucocele).

Treatment for LAMN I

Being diagnosed with a LAMN I means the growth has remained inside the appendix and does not require any further treatment. We do however like to monitor patients with yearly CT scans and blood tests for 5 years to make sure no spread develops, which very rarely happens.

Since we started the service, we have never seen a patient with a LAMN I lesion develop more advanced disease. If there is evidence that the appendix has burst or leaked its contents into the abdomen, the lesion becomes a LAMN II, and this does require a different approach with potentially other operations and treatments.

Last updated: July 2023