Serous borderline tumour is a non-cancerous type of ovarian tumour. These tumours are described as having low malignant potential. This means there is a small risk the tumour will turn into cancer over time. The behaviour of a serous borderline tumour is thought to fall in between a serous cystadenoma which is a non-cancerous tumour and low-grade serous carcinoma which is a type of cancer.
The ovaries are part of the female reproductive tract. They are small organs that are attached to the uterus by the fallopian tubes. The outer surface of the ovaries are lined by a thin layer of specialized tissue called the epithelium that forms a barrier around the outside of the ovary.
The organs inside the abdomen are lined by a thin layer of tissue called the peritoneum that is made up of similar cells. The ovaries also contain large cells called eggs. The tissue below the epithelium is called the stroma.
For most women, the diagnosis of serous borderline tumour is only made when the entire tumour has been surgically removed and sent to a pathologist for examination. The fallopian tube and uterus may be removed at the same time.
Your surgeon may request an intraoperative or frozen section consultation from your pathologist. The diagnosis made by your pathologist during the intraoperative consultation can change the type of surgery performed or the treatment offered after the surgery is completed.
Serous borderline tumours develop from the epithelial cells on the outer surface of the ovary. The tumour is usually made up of many small spaces. Pathologists call these spaces cysts. The walls of the cysts can be thin or thick and more solid areas may be found inside some of the cysts. Pathologists sometimes call these solid areas excrescences.
The inside of the cysts are lined by specialized serous cells. These cells produce a clear fluid that fills the inside of the tumour. The cysts with thick walls and the solid areas may have small finger-like projections of tissue. Pathologists call these projections papillary. The more solid areas and papillary projections are what make a serous borderline tumour different from a serous cystadenoma.
Your pathologist will carefully examine the tumour under the microscope for two microscopic features that will help determine how the tumour will behave over time. Micropapillary growth and microinvasion are early signs of cancer and both are associated with worse prognosis.
All ovarian tumours are examined to see if there are any holes or tears in the outer surface of the tumour or ovary. The outer surface is referred to as the capsule. The capsule is described as intact if no holes or tears are identified. The capsule is described as ruptured if the outer surface contains any large holes or tears.
This information is important because a capsule that ruptures inside the body may spill tumour cells into the abdominal cavity. A ruptured capsule is associated with a worse prognosis and is used to determine the tumour stage (see Pathologic stage below).
Your pathologist will carefully examine the tissue under the microscope to see if there are any tumour cells on the surface of the ovary. Tumour cells on the surface of the ovary increase the risk that the tumour will spread to other organs in the pelvis or abdomen. It is also used to determine the tumour stage (see Pathologic stage below).
The organs inside the abdomen are lined by a thin layer of tissue called the peritoneum. Your pathologist will carefully examine any tissue from the peritoneum to look for tumour cells. Tumour cells in the peritoneum are called implants. The presence of peritoneal implants is important because it is used to determine the tumour stage (see Pathologic stage below) and becasue invasive implants are associated with a worse prognosis.
There are two kinds of implants.
Small samples of tissue are commonly removed in a procedure called a biopsy to see if tumour cells have spread to the pelvis or abdomen. These biopsies which are often called omentum or peritoneum are sent for pathological examination along with the tumour.
Other organs (such as the bladder, small intestine, or large intestine) are not typically removed and sent for pathological examination unless they are directly attached to the tumour. In these cases, your pathologist will examine each organ under the microscope to see if there are any tumour cells attached to those organs. Tumour cells in other organs are used to determine the tumour stage (see Pathologic stage below).
Lymph nodes are small immune organs located throughout the body. Tumour cells can travel from the tumour to a lymph node through lymphatic channels located in and around the tumour (see Lymphovascular invasion above). The movement of tumour cells from the tumour to a lymph node is called metastasis.
The tumour cells from a serous borderline tumour can spread to lymph nodes. If tumour cells are found in a lymph node it will be described in your pathology report. Unlike other types of tumours, cells from a serous borderline tumour found in a lymph node are not associated with a worse prognosis.
The pathologic stage for serous borderline tumour is based on the TNM staging system, an internationally recognized system originally created by the American Joint Committee on Cancer. This system uses information about the primary tumour (T), lymph nodes (N), and distant metastatic disease (M) to determine the complete pathologic stage (pTNM). Your pathologist will examine the tissue submitted and give each part a number. In general, a higher number means more advanced disease and a worse prognosis.