by Jason Wasserman MD PhD FRCPC
April 19, 2026
Adult-type granulosa cell tumor is a rare type of ovarian cancer that develops from granulosa cells — specialized cells in the ovary that normally support egg development and produce the hormone estrogen. It is the most common type of sex cord-stromal tumor, a group of ovarian tumors that arise from the hormone-producing supporting cells of the ovary rather than from the surface epithelium. Adult-type granulosa cell tumor account for about 1% of all ovarian tumors and most often affect women around the time of menopause, though they can occur at any age. Although it is a cancer, it typically grows slowly, and the majority of cases are diagnosed at an early stage. This article will help you understand the findings in your pathology report — what each term means and why it matters for your care.
What are the symptoms?
The symptoms of adult-type granulosa cell tumor are often caused by the hormones the tumor produces. Because granulosa cells normally produce estrogen, most of these tumors produce excess estrogen, leading to a characteristic set of symptoms. Abnormal uterine bleeding is the most common presenting symptom, particularly unexpected bleeding after menopause, which brings most patients to medical attention. In premenopausal women, the tumor may cause irregular or heavy menstrual periods. The excess estrogen can also cause the lining of the uterus (endometrium) to become abnormally thick, a condition called endometrial hyperplasia. In some cases, this can progress to endometrial cancer if left untreated.
A smaller number of tumors produce excess androgens (male hormones) rather than or in addition to estrogen, which can cause increased body hair, acne, or a deepening of the voice. Abdominal or pelvic pain and swelling are common, particularly when the tumor grows large. Occasionally, the tumor can rupture, causing internal bleeding and sudden, severe abdominal pain that requires urgent medical attention.
What causes an adult-type granulosa cell tumor?
The exact cause is not fully understood, but a specific mutation in a gene called FOXL2 is found in nearly all adult-type granulosa cell tumors — making this one of the most molecularly consistent tumor types in all of oncology. The FOXL2 gene normally helps control the development and function of granulosa cells. The mutation — a single specific change at a single position in the gene — causes the FOXL2 protein to malfunction, driving granulosa cells to grow abnormally. This mutation occurs only in the tumor cells themselves and is not inherited from parents or passed on to children.
Adult-type granulosa cell tumor is not associated with BRCA mutations, Lynch syndrome, or other hereditary cancer syndromes that affect epithelial ovarian cancers. Most cases occur without any identifiable predisposing condition.
How is the diagnosis made?
The diagnosis is usually made after the tumor is surgically removed and examined under the microscope by a pathologist. If surgery is performed, the pathologist also examines other tissues removed at the same time — including the fallopian tube, peritoneal biopsies, omentum, and lymph nodes — to determine whether the tumor has spread.
Under the microscope, an adult-type granulosa cell tumor can show many different growth patterns. The most common pattern is the diffuse one, in which cells form solid sheets. Other patterns include cords, islands, trabeculae (bands of cells), and small rings of cells surrounding tiny fluid-filled spaces. These small, circular structures are called Call–Exner bodies and are a classic, diagnostically helpful feature of this tumor type. A defining microscopic feature of the tumor cells is the appearance of their nuclei — they are pale and oval with a longitudinal groove or fold down the center, giving them a distinctive “coffee bean” appearance. The number of mitotic figures (dividing cells) is usually low, reflecting the slow-growing nature of this tumor.
To confirm the diagnosis and distinguish adult-type granulosa cell tumor from other ovarian tumors that can look similar — including fibroma, thecoma, and undifferentiated carcinoma — the pathologist uses immunohistochemistry (IHC). Adult-type granulosa cell tumors are typically positive for FOXL2, calretinin, inhibin, SF1, CD99, WT1, and estrogen receptor — all markers that reflect their granulosa cell origin. Markers such as PAX8, cytokeratin 7 (CK7), and EMA are usually negative, helping exclude epithelial ovarian carcinomas. In some cases, molecular testing is used to look directly for the characteristic FOXL2 mutation, which is present in nearly all cases and can confirm the diagnosis when microscopic features or IHC results are ambiguous.
Once the diagnosis is confirmed, imaging — typically CT of the abdomen and pelvis — is performed to determine the extent of disease. Blood tests measuring serum inhibin and estradiol are performed, as these provide a baseline for monitoring after treatment.
Histologic grade
Adult-type granulosa cell tumor is not assigned a histologic grade using the standard grading systems applied to ovarian carcinomas. Those systems are designed for epithelial cancers and do not translate meaningfully to sex cord-stromal tumors. The most important factors predicting outcomes are stage, capsule status, and whether all visible tumor can be removed at surgery. A phenomenon called high-grade transformation — in which an area of the tumor shows markedly more abnormal-looking cells and increased mitotic activity than the rest — can occasionally be observed and is associated with more aggressive behavior, but it is distinct from routine histologic grading.
Tumor spread
The pathologist examines the surface of the ovary and the nearby fallopian tube, as well as any peritoneal biopsies and omentum submitted at surgery, to determine whether the tumor has spread beyond the ovary. The peritoneum — the thin lining of the abdominal cavity — and the omentum — the fatty tissue hanging from the stomach and intestines — are common sites of spread. If the surgeon identifies direct attachment of the tumor to another organ, such as the bladder, small intestine, or large intestine, that organ may also be removed and examined. The presence of tumor cells outside the ovary increases the stage and is associated with a higher risk of recurrence.
Ovarian capsule status
The outer covering of the ovary is called the capsule. The pathologist will note whether the capsule is intact or ruptured, and whether a tumor is present on the outer surface. These findings affect the stage and prognosis:
- Intact capsule, no surface tumor — Suggests the tumor is still contained within the ovary, associated with an earlier stage and better prognosis.
- Ruptured capsule or tumor on the surface — Even when no other spread is found, capsule rupture or surface involvement increases the stage. It is associated with a higher risk of recurrence, including in otherwise stage I disease.
- Intraoperative rupture — If the capsule ruptures during surgery rather than before, this is noted separately and also affects staging.
Lymphovascular invasion
Lymphovascular invasion means that tumor cells have been found inside small blood vessels or lymphatic channels within the tissue. This finding suggests that tumor cells may have had an opportunity to travel to lymph nodes or distant sites, and it can influence staging and treatment planning.
Lymph nodes
Lymph nodes are small, bean-shaped structures that help filter the body’s lymphatic fluid and support the immune system. In ovarian tumor surgery, lymph nodes from the pelvis and along the major abdominal blood vessels (para-aortic nodes) may be removed and examined. Lymph node involvement is uncommon in adult-type granulosa cell tumor, particularly in early-stage disease. Still, when present, it is associated with a higher stage and greater risk of recurrence.
The pathology report will describe:
- The total number of lymph nodes examined
- The number of lymph nodes containing tumor cells
- The size of the largest tumor deposit
- The location of any involved nodes (pelvic vs. para-aortic)
Lymph node deposits are classified by size. Isolated tumor cells (measuring 0.2 mm or less) are recorded as pN0(i+) and are not counted as definitive metastases in all staging systems. Deposits between 0.2 mm and 10 mm are classified as pN1a (small metastases), and deposits larger than 10 mm are classified as pN1b (large metastases). These size distinctions affect the N stage.
Biomarker and molecular testing
Routine biomarker testing of the type performed for epithelial ovarian cancers — such as BRCA mutation testing, HRD testing, or MMR/MSI testing — is not standard for adult-type granulosa cell tumor, which arises through an entirely different molecular pathway. The most clinically important markers for this tumor type are FOXL2 and inhibin.
FOXL2
FOXL2 is a gene that produces a protein essential for the normal development and function of granulosa cells. A specific point mutation in FOXL2 — the same single change in virtually every case — is the molecular hallmark of adult-type granulosa cell tumor, present in approximately 95% of cases. Testing for the FOXL2 mutation is performed by molecular sequencing on tumor tissue. It is most useful when the diagnosis is uncertain based on microscopic appearance and IHC alone — for example, when a tumor has unusual features or when the differential diagnosis includes another sex cord-stromal tumor. Results are reported as “FOXL2 mutation detected” or “not detected”. A positive result strongly supports the diagnosis of adult-type granulosa cell tumor.
Inhibin (serum marker)
Inhibin is a hormone normally produced by granulosa cells. Because adult-type granulosa cell tumors arise from these cells, they almost always produce elevated levels of inhibin, which can be detected in the blood. Serum inhibin is not reported in the pathology report itself — it is a blood test ordered by the treating physician — but it is one of the most valuable tools for monitoring this tumor after treatment. After successful surgery, serum inhibin levels should fall to normal. A rising inhibin level during follow-up can be an early signal of tumor recurrence, often detectable before any abnormality appears on imaging. Serum estradiol (estrogen) can serve a similar monitoring role. Long-term inhibin monitoring is recommended given the risk of very late recurrence unique to this tumor type.
Endometrial assessment
Because excess estrogen produced by the tumor frequently causes endometrial hyperplasia — abnormal thickening of the uterine lining — the endometrium (uterine lining) should be evaluated at the time of diagnosis. In some patients, an endometrial biopsy or sampling is performed before or during surgery. If endometrial hyperplasia or an early endometrial cancer is identified, this affects surgical planning. Patients whose uterus is preserved after surgery should continue to be monitored for endometrial changes during follow-up.
For more information about biomarker testing in ovarian cancer, see the Biomarkers and Molecular Testing section.
Pathologic stage (pTNM)
Staging describes how far the tumor has spread. Adult-type granulosa cell tumor is staged using the AJCC TNM system, which closely corresponds to the FIGO staging system used by gynecologic oncologists. The stage is made up of three components: T (how far the tumor has grown locally), N (whether it has spread to lymph nodes), and M (whether it has spread to distant organs). M stage is determined by imaging and is not typically assigned in the pathology report unless distant spread was sampled at surgery. The vast majority of adult-type granulosa cell tumors are diagnosed at stage I.
Tumor stage (pT)
- pT1 (FIGO Stage I) — Tumor is limited to one or both ovaries.
- pT1a — Tumor confined to one ovary; capsule intact; no tumor on the outer surface; no tumor cells in abdominal fluid.
- pT1b — Tumor involves both ovaries; capsules intact; no tumor on the outer surface; no tumor cells in abdominal fluid.
- pT1c — Tumor limited to one or both ovaries but with capsule rupture, tumor on the outer surface, or cancer cells in abdominal fluid or washings.
- pT2 (FIGO Stage II) — Tumor involves one or both ovaries with spread into the pelvis.
- pT2a — Spread to the uterus or fallopian tubes.
- pT2b — Spread to other pelvic tissues.
- pT3 (FIGO Stage III) — Tumor has spread beyond the pelvis to the peritoneum or regional lymph nodes.
- pT3a — Microscopic spread to the peritoneum outside the pelvis, with or without regional lymph node involvement.
- pT3b — Visible tumor deposits up to 2 cm on the peritoneum outside the pelvis.
- pT3c — Visible tumor deposits larger than 2 cm outside the pelvis, or spread to the outer surface of the liver or spleen.
Nodal stage (pN)
- pN0 — No cancer cells found in regional lymph nodes.
- pN0(i+) — Only isolated tumor cells (0.2 mm or less) found in lymph nodes; not counted as definitive metastases in all staging systems.
- pN1 — Cancer cells present in regional lymph nodes.
- pN1a — Tumor deposits up to 10 mm.
- pN1b — Tumor deposits larger than 10 mm.
What is the prognosis?
The prognosis for an adult-type granulosa cell tumor is generally favorable, particularly for the large majority of patients diagnosed at stage I. The 10-year survival rate for early-stage disease is approximately 90–95%. However, this tumor has a well-recognized tendency to recur, and a unique feature of adult-type granulosa cell tumor is that recurrence can happen very late, sometimes 10, 15, or even 20 or more years after the initial diagnosis. This is one of the longest recurrence intervals of any cancer, and it means that lifelong follow-up is necessary even for patients who appear cured.
Factors associated with a higher risk of recurrence or worse outcomes include:
- In the advanced stage, Spread beyond the ovary at diagnosis is the most important adverse prognostic factor.
- Capsule rupture — Rupture of the ovarian capsule before or during surgery increases the risk of recurrence even in otherwise stage I disease.
- Residual disease after surgery — Complete removal of all visible tumor is strongly associated with better outcomes, particularly in advanced disease.
- Bilateral involvement — Tumor in both ovaries is uncommon but is associated with a higher stage.
- High-grade transformation — The rare finding of areas with markedly abnormal cells and high mitotic activity within the tumor may be associated with more aggressive behavior.
- Rising serum inhibin — An increase in inhibin during follow-up is the most sensitive early indicator of recurrence and should prompt further evaluation even before symptoms develop.
What happens after the diagnosis?
Treatment is planned by a multidisciplinary team that typically includes a gynecologic oncologist, a medical oncologist, a pathologist, and a radiologist. The approach depends on the patient’s age, stage, and whether fertility preservation is a consideration.
Surgery is the primary treatment. For women who have completed childbearing, standard surgery involves the removal of both ovaries, both fallopian tubes, and the uterus (total abdominal hysterectomy with bilateral salpingo-oophorectomy), along with assessment of the peritoneum, omentum, and lymph nodes. Removal of the uterus is important in this tumor type because excess estrogen from the tumor frequently causes endometrial hyperplasia, and a concurrent endometrial cancer is found in a minority of patients. For younger women who wish to preserve fertility and have unilateral stage IA disease with an intact capsule, fertility-sparing surgery — removing only the affected ovary and tube while leaving the uterus and other ovary in place — can be considered after careful discussion of the risks.
For patients with stage IA disease and an intact capsule, surgery alone is generally considered sufficient. For patients with higher-stage disease, capsule rupture, or residual tumor after surgery, chemotherapy is recommended. The most commonly used regimen is BEP (bleomycin, etoposide, and cisplatin), which is standard for ovarian sex cord-stromal tumors. Hormonal therapy and radiation therapy may be considered in selected cases of recurrent disease.
Given the risk of very late recurrence, long-term follow-up is essential and must continue indefinitely. Surveillance typically includes regular clinical assessments, serum inhibin and estradiol monitoring, and imaging studies. Because a rising inhibin level can signal recurrence before any symptoms or imaging abnormality appear, patients should be aware of the importance of maintaining long-term follow-up even when they feel completely well.
Questions to ask your doctor
- What stage was my tumor, and what does that mean for my prognosis and follow-up?
- Was the tumor confined to one ovary, and was the ovarian capsule intact?
- Was the tumor completely removed, and was any tumor left behind?
- Was the FOXL2 mutation tested, and was it detected?
- Was the uterine lining (endometrium) evaluated, and were any abnormalities found?
- If fertility-sparing surgery was performed, what is the recommendation for the remaining ovary and uterus in the future?
- Is chemotherapy recommended, and if so, which regimen?
- What serum markers — inhibin, estradiol — should be monitored, and how often?
- What imaging schedule do you recommend for long-term surveillance?
- What symptoms should I watch for that might suggest recurrence?
- Given that this tumor can recur very late, how long do I need to continue follow-up?
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