Canadian Cancer Society logo

Ovarian cancer

You are here: 

Tumours of borderline malignancy

Tumours of borderline malignancy are epithelial tumours that don’t clearly appear to be cancerous. They account for approximately 15% of all epithelial ovarian tumours. They may occur in one or both ovaries.

These tumours are also known as:

  • tumours or ovarian cancer of low malignant potential (LMP)
  • borderline tumours
  • atypical proliferative tumours
  • borderline epithelial ovarian cancer

Tumours of borderline malignancy are different from typical ovarian cancers.

  • Although the cells of the tumour appear malignant (cancerous), they have not invaded the underlying or nearby tissue.
  • If they spread outside the ovary into the abdominal cavity, they may grow on the lining of the abdomen, but they don’t grow into it.
  • The tumours grow slowly and most are stage I at diagnosis.
  • The tumours tend to develop in women at a younger age than most ovarian cancers.

Types of tumours include:

  • serous tumours
  • mucinous tumours (gastrointestinal type or endocervical-like type)
  • endometrioid tumours
  • clear cell tumours
  • transitional cell tumours (Brenner tumour) – usually benign

Stories

Eleanor Rudd We realize that our efforts cannot even be compared to what women face when they hear the words ... ‘you have cancer.’

Read more

Support from someone who has ‘been there’

Illustration of conversation

The Canadian Cancer Society’s peer support program is a telephone support service that matches cancer patients and their caregivers with specially trained volunteers.

Learn more