Serous cystadenoma of the ovary

by Jason Wasserman MD PhD FRCPC
May 15, 2023

What is a serous cystadenoma?

A serous cystadenoma is a very common non-cancerous type of ovarian tumour. It develops from the cells on the surface of the ovary. While these tumours are non-cancerous, they can grow to be very large in size and as a result, can cause significant symptoms for many patients.

Gynecological tract

What are the symptoms of a serous cystadenoma?

Small tumours usually do not cause any symptoms and are only found incidentally when imaging is performed for another reason. Large tumours may cause symptoms such as abdominal pressure, pain, or bloating.

What causes a serous cystadenoma?

At present doctors do not know what causes a serous cystadenoma.

How is the diagnosis of serous cystadenoma made?

For most women, the diagnosis of serous cystadenoma 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.​

What does a serous cystadenoma look like under the microscope?

Most tumours are similar in look and feel to a balloon filled with fluid. The inside of the tumour may be one large space or many small spaces filled with fluid. Pathologists call these spaces cysts.

When the tumour is examined under the microscope, the tissue on the inside of the cysts is made up of an abnormal type of epithelium made up of serous cells. These cells produce a fluid that fills the inside of the tumour. Some tumours will have thicker walls or solid areas in the centre of the tumour. These tumours contain more cells and less fluid and are called serous adenofibromas. However, they are still non-cancerous.

ovary serous cystadenoma
Serous cystadenoma of the ovary. This picture shows the wall of the tumour lined by serous cells.
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