Your pathology report for adult type granulosa cell tumour

by Jason Wasserman MD PhD FRCPC
August 27, 2025

Adult type granulosa cell tumor is a rare type of ovarian cancer. It begins with granulosa cells, specialized cells in the ovary that support egg development and hormone production. In this tumor, granulosa cells grow in abnormal patterns and may be mixed with other supporting ovarian cells. Although it is a cancer, this tumor usually grows more slowly than many other types of ovarian cancer.

How common is adult type granulosa cell tumor?

This tumor is the most common type of sex cord–stromal tumor, which is a group of ovarian tumors that start from the hormone-producing cells of the ovary. Even so, adult type granulosa cell tumor is rare overall and accounts for about 1 percent of all ovarian tumors.

Who gets adult type granulosa cell tumor?

This tumor can occur at any age but is most often found in women around the time of menopause.

What are the symptoms of adult type granulosa cell tumor?

The symptoms of adult type granulosa cell tumor are often related to the hormones produced by the tumor. Many patients experience abnormal uterine bleeding, especially after menopause. In younger women, the tumor may cause irregular menstrual cycles. Some patients develop endometrial hyperplasia, which means the lining of the uterus becomes too thick, and in rare cases this can lead to cancer of the uterine lining.

A smaller number of patients experience symptoms related to excess androgen hormones, which may include increased body hair or a deepening of the voice. Abdominal or pelvic pain and swelling are common, especially if the tumor grows large. Occasionally, the tumor can rupture, causing internal bleeding and sudden severe pain.

What causes adult type granulosa cell tumor?

The exact cause is unknown. However, nearly all adult type granulosa cell tumors have a change in a gene called FOXL2. A gene is a set of instructions that tells a cell how to grow and function. The FOXL2 change is not inherited from parents and cannot be passed to children. It only happens in the tumor itself and causes the granulosa cells to grow abnormally.

How is the diagnosis made?

The diagnosis is usually made after the tumor is surgically removed and examined under the microscope by a pathologist. The microscopic features together with the results of special tests such as immunohistochemistry or molecular tests, such as detection of the FOXL2 mutation, help confirm the diagnosis. Blood tests for inhibin can also help doctors monitor for recurrence after treatment.

What does adult type granulosa cell tumor look like under the microscope?

Under the microscope, the tumor can show many different growth patterns. The most common is called diffuse, where the cells form a solid sheet. Other patterns include cords, islands, or small rings of cells around tiny spaces filled with fluid. These small circular structures are called Call–Exner bodies and are a classic feature of this tumor.

The tumor cells usually have pale oval nuclei with grooves, which are folds in the center of the cell that give them a “coffee bean” appearance. The number of dividing cells is usually low, meaning the tumor does not grow very quickly.

What other tests may be ordered to confirm the diagnosis?

In addition to looking at the tumor under the microscope, pathologists often perform special tests to confirm the diagnosis of adult type granulosa cell tumor. One of the most common methods is called immunohistochemistry. This technique uses stains to highlight specific proteins inside the tumor cells.

Adult type granulosa cell tumors typically test positive for proteins such as FOXL2, calretinin, inhibin, SF1, estrogen receptor, pan-cytokeratin, CD99, and WT1. These markers support the diagnosis because they are normally found in granulosa cells. Other markers, such as PAX8, cytokeratin 7, and EMA, are usually negative, which helps rule out other types of ovarian tumors.

Some tumors closely resemble other ovarian growths such as fibroma or thecoma. Pathologists use markers, such as reticulin, FOXL2, inhibin, calretinin, and SF1, to confirm the diagnosis.

In some cases, molecular testing such as next-generation sequencing may also be used to look for the characteristic FOXL2 gene change, which is found in nearly all adult type granulosa cell tumors.

Were tumor cells seen on the surface of the ovary or fallopian tube?

Pathologists carefully examine the surface of the ovary and the nearby fallopian tube for tumor cells. If tumor cells are found on these surfaces, it means that the tumor has spread beyond where it started. This type of spread is called metastasis.

Finding tumor cells on the surface of the ovary or fallopian tube is important because it changes the stage of the tumor. A higher stage means the tumor has a greater risk of coming back in the future.

Why is it important if the tumor was received intact or ruptured?

When examining an ovarian tumor, pathologists look closely at the outer covering of the ovary, which is called the capsule. If the capsule is smooth and has no tears or holes, it is described as intact. If it has large tears or breaks, it is described as ruptured.

If the tumor is received in many pieces, it can be difficult for the pathologist to know whether the rupture happened inside the body or during surgery. A capsule that ruptures inside the body is important because it can allow tumor cells to spill into the abdominal cavity. This increases the risk of the tumor spreading and is associated with a worse prognosis. For this reason, rupture of the capsule is used to determine the tumor stage.

Has the tumor spread to other organs or tissues in the pelvis or abdomen?

During surgery, small samples of tissue may be removed from the pelvis and abdomen to see if the tumor has spread. These samples are often taken from the peritoneum, which is a thin lining that covers the inside of the abdomen, and from the omentum, which is a fatty tissue that hangs down from the stomach and intestines. The omentum is a common site where granulosa cell tumors can spread.

If the surgeon sees that the tumor is directly attached to another organ, such as the bladder, small intestine, or large intestine, that organ may also be removed and sent for examination. The pathologist studies these samples under the microscope to check for cancer cells.

If tumor cells are found in these other organs or tissues, it means the tumor has spread beyond the ovary. This information is used to determine both the tumor stage (T) and whether the cancer has spread to distant sites (M).

How is adult type granulosa cell tumor staged?

Staging describes how far the tumor has spread. Doctors use international systems such as TNM and FIGO to assign a stage.

• Stage I means the tumor is limited to one or both ovaries.

• Stage II means it has grown into other pelvic organs.

• Stage III means it has spread to the abdomen or lymph nodes.

• Stage IV means it has spread to distant sites such as the liver or lungs.

Most patients are diagnosed at stage I, when the tumor is still confined to the ovary.

What is the prognosis for adult type granulosa cell tumor?

The outlook for patients with adult type granulosa cell tumor is generally good, especially if the tumor is found at stage I. The 10-year survival rate for patients with early stage disease is about 90 to 95 percent. However, about 10 to 15 percent of patients with stage I tumors and up to 30 percent of patients overall may develop recurrence. A unique feature of this tumor is that it can return many years later, sometimes more than 20 years after the first diagnosis.

The most important factor in predicting outcome is the stage of the tumor at diagnosis. Tumor rupture, even in stage I, increases the risk of recurrence. For patients whose tumor has spread beyond the ovary, whether all visible tumor was removed at surgery is another key factor. High-grade transformation, which means the tumor cells look much more abnormal under the microscope, may also be linked with more aggressive behavior.

Because of the possibility of late recurrence, patients need long-term follow-up. Doctors often use blood tests for inhibin and regular imaging studies to monitor for signs of return.

Questions to ask your doctor

• Was my tumor confined to the ovary or had it spread?

• Was the tumor completely removed during surgery?

• What stage was my tumor?

• Do I need blood tests for inhibin or other markers to monitor for recurrence?

• How often should I return for follow-up?

• What symptoms should I watch for that may suggest the tumor has come back?