by Jason Wasserman MD PhD FRCPC
October 5, 2024
An adult type granulosa cell tumour (GCT) is a rare and slow-growing ovarian cancer that originates from specialized granulosa cells in the ovary. This type of tumour belongs to a category of ovarian tumours called sex-cord stromal tumours. Despite its name, this cancer can occur at any age, although the majority of patients are perimenopausal.
Almost all adult type granulosa cell tumours contain a mutation in the FOXL2 gene. However, doctors do not know what causes this mutation to occur.
Some adult type granulosa cell tumours will produce hormones such as estrogen, which can result in symptoms such as abnormal vaginal bleeding and breast tenderness. Androgen-producing tumours may result in symptoms such as increased body hair growth and voice changes. Small tumours and those that do not produce any hormones may not cause symptoms and may only be discovered when pelvic imaging is performed for another reason.
An adult type granulosa cell tumour is usually diagnosed after it is removed during surgery. Imaging studies like ultrasound or CT scans may show an ovarian mass, but these tests cannot confirm the exact nature of the tumour. A pathologist examines the tumour tissue under a microscope to identify its characteristic features. Immunohistochemistry (IHC) may also be performed to detect specific proteins that support the diagnosis.
Under microscopic examination, adult type granulosa cell tumour is composed of medium-sized tumour cells arranged in various architectural patterns, often described as cords, trabecular, or insular. Unique round groups of cells called Call-Exner bodies may also be seen. The nucleus (the part of the cell that holds the genetic material) is often round to oval-shaped with an irregular membrane that can in part a “coffee bean” look to the cell. A small number of mitotic figures (dividing cells) may be seen.
Immunohistochemistry (IHC) is a technique that pathologists use to detect specific proteins in tumour cells. It helps confirm the diagnosis of certain types of tumours by identifying characteristic markers. For adult-type granulosa cell tumours, IHC is performed to look for proteins typically found in these cells. The expected results include positive staining for FOXL2, calretinin, inhibin, SF1, estrogen receptor (ER), pan-cytokeratin, CD99, and WT1. Markers such as PAX8, cytokeratin 7 (CK7), and EMA are usually negative.
The tumour cells in an adult type GCT can spread from the ovary to another nearby organ such as the fallopian tube or the ovary on the other side of the body. If tumour cells are seen on the surface of the fallopian tube or ovary, it suggests that they have spread there from the tumour. The spread of cells from the tumour to another body site is called metastasis. This information is important because a tumour that has spread or metastasized from one organ to another is given a higher tumour (T) stage.
All ovarian tumours are examined to see if there are any holes or tears in the ovary’s outer (capsular) surface. The capsular surface is described as intact if no holes or tears are identified. The capsular surface is defined as ruptured if it contains large holes or tears. If the ovary or tumour is received in multiple pieces, it may not be possible for your pathologist to tell if the capsular surface has ruptured. This information is important because a capsular surface 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 (T) stage.
Small tissue samples are commonly removed in a biopsy to see if tumour cells have spread outside the ovary. These biopsies, often from a tissue in the pelvis and abdomen called the peritoneum, are sent to your pathologist to see if the tumour has spread or metastasized. The omentum is an abdominal organ that is a common site of tumour spread or metastasis. This organ is often entirely removed and examined by your pathologist. 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 or the tumour spreading to these organs is seen by your surgeon. In these cases, your pathologist will examine each organ under the microscope to see if any cancer cells are attached to those organs. The presence of tumour cells in other organs is used to determine the tumour (T) stage and distant metastatic disease (M) stage.
Doctors wrote this article to help you read and understand your pathology report. Contact us with any questions about this article or your pathology report. Read this article for a more general introduction to the parts of a typical pathology report.