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. This type of growth is not considered cancerous.

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 passed 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 need to have their appendix removed. Others have discomfort and are investigated with an ultrasound or CT scan and the appendix can appear enlarged (this is called a mucocele).

What does this mean for you?

Your case has been carefully reviewed by our specialist team. Being diagnosed with a LAMN I means the growth has remained inside your appendix.

We reviewed all available information about these types of lesions, and we are sure that:

  • the risk of this condition causing you problems in the future is extremely low
  • no further treatment is needed
  • no ongoing follow-up appointments or scans are required

This means you can return to your usual activities without any additional monitoring for this condition. 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.

The colorectal and peritoneal oncology centre

The colorectal and peritoneal oncology centre has an international reputation for treating advanced and early colorectal cancer, appendix tumours, peritoneal tumour, anal cancer and tumours within the pelvis.

The service will provide:

  • ongoing advice and support for patients, their partners and families
  • information and advice about treatment and treatment options
  • a point of contact should problems arise
  • a link with other health care professionals involved in your care
  • referral to specialist services

Who can contact us?

Any healthcare professional who needs information and advice. Any patient who would like referring can contact the service themselves or by referral from another healthcare professional. We are happy to speak to partners, friends and family, providing the patient has given consent.

If you know the name of your consultant, please contact their secretary directly:

  • Professor A G Renehan: 0161 918 2189
  • Mr C R Selvasekar: 0161 918 2310
  • Professor O Aziz: 0161 918 2057
  • Mr H W Clouston: 0161 918 2391
  • Mr J Wild: 0161 918 7352
  • Mr R Fish: 0161 918 2391
  • Mr P Sutton: 0161 446 3366
  • Miss L Martin Roman: 0161 918 2310
  • Miss R Clifford: 0161 446 3366

Last updated: April 2026