by Jason Wasserman MD PhD FRCPC
April 18, 2026
Juvenile type granulosa cell tumor is a rare type of ovarian cancer that develops from granulosa cells — specialized cells in the ovary that normally produce the hormone estrogen and support the development of egg cells. It belongs to a group of ovarian tumors called sex cord-stromal tumors. Unlike most ovarian cancers, which develop in adults in their 50s and 60s, juvenile type granulosa cell tumor almost always develops in girls and young women before the age of 30, and many cases occur in children before puberty. The word “juvenile” refers to this young age of onset and to the immature appearance of the tumor cells under the microscope — not to whether the patient is currently young. 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?
Symptoms depend on whether the tumor produces hormones and on the patient’s age. Many juvenile type granulosa cell tumors produce estrogen, which can cause distinctly different effects at different life stages.
In prepubertal girls, excess estrogen from the tumor causes precocious puberty — the early appearance of breast development, pubic hair, and menstrual-like bleeding before the normal age of puberty. This is often the first sign that brings the tumor to medical attention. In adolescents and young women, the tumor may cause irregular menstrual periods, heavy bleeding, or abdominal pain related to a pelvic mass. Some tumors produce androgens (male hormones) instead of or in addition to estrogen, which can cause increased body hair growth, acne, or changes to the voice. Tumors that do not produce hormones may cause no symptoms and be discovered incidentally during imaging performed for another reason, or when a large mass becomes palpable.
What causes juvenile type granulosa cell tumor?
The exact cause is not fully understood, but genetic changes within the tumor cells play an important role. Mutations in a gene called GNAS — which helps regulate how cells receive and respond to hormonal signals — are found in approximately 30% of juvenile type granulosa cell tumors. This mutation causes the signaling pathway to become abnormally active, which drives abnormal cell growth.
A small number of cases are associated with rare bone disorders called Ollier disease (multiple enchondromatosis) and Maffucci syndrome, both of which are caused by mutations affecting the same signaling pathway. These associations suggest a shared underlying molecular mechanism in a subset of patients. The vast majority of cases, however, occur without any associated condition or identifiable inherited cause.
Unlike the more common types of ovarian cancer, juvenile type granulosa cell tumor is not associated with BRCA mutations or Lynch syndrome.
How is the diagnosis made?
The diagnosis is made after a tissue sample is examined under the microscope by a pathologist. In most cases, the diagnosis is only possible after the entire tumor is surgically removed, as the microscopic features required to confirm it require examination of the entire specimen. If surgery is performed to remove the ovary and tumor, the pathologist also examines any other tissues sent at the same time — such as the fallopian tube, peritoneal biopsies, and omentum — to determine whether the tumor has spread.
Under the microscope, juvenile type granulosa cell tumor is composed of medium-sized cells with round nuclei and pale to pink (eosinophilic) cytoplasm. The cells are typically arranged in large sheets or nodular groups. A distinctive feature is the presence of follicle-like spaces — round cavities inside the tumor that resemble the follicles normally found in the ovary — which may be filled with fluid or secretions. Compared to the adult type granulosa cell tumor, juvenile type tumors typically show more nuclear atypia (abnormal-looking nuclei) and a higher number of mitotic figures (dividing cells). The adult type characteristically shows “coffee-bean” nuclear grooves, which are absent or inconspicuous in the juvenile type.
To confirm the diagnosis and distinguish juvenile type granulosa cell tumor from other ovarian tumors that can look similar — including small cell carcinoma of the ovary and other sex cord-stromal tumors — the pathologist uses immunohistochemistry (IHC). The tumor cells are typically positive for calretinin, inhibin, SF1, CD99, and WT1, all of which are markers of sex cord-stromal differentiation. Markers such as PAX8, cytokeratin 7 (CK7), and EMA are usually negative, which helps exclude epithelial ovarian carcinomas. These IHC results, interpreted alongside the microscopic features, confirm the diagnosis.
Once the diagnosis is confirmed, imaging — typically CT of the abdomen and pelvis, and sometimes MRI — is performed to determine the extent of disease. Blood tests measuring serum inhibin and estradiol levels are also performed, as elevated levels support the diagnosis and provide a baseline for monitoring after treatment.
Histologic grade
Juvenile type granulosa cell tumor is not assigned a histologic grade using the standard grading systems applied to ovarian carcinomas. Those grading systems — which assess how closely tumor cells resemble normal tissue — are designed for epithelial cancers and do not apply meaningfully to sex cord-stromal tumors. The most important factors predicting outcomes in juvenile type granulosa cell tumor are the stage at diagnosis, whether the ovarian capsule ruptured, and the amount of tumor remaining after surgery, not the histologic grade.
Tumor spread
The pathologist examines all submitted tissue to determine whether the tumor has spread beyond the ovary. Juvenile type granulosa cell tumor most commonly spreads to the surface of the fallopian tube, the peritoneum (the thin lining of the abdominal cavity), and the omentum. The omentum — a fatty tissue hanging from the stomach and intestines inside the abdomen — is a common site of spread for ovarian tumors and is often removed during surgery and examined in full. Spread to other pelvic organs, such as the uterus or bladder, is less common. 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 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 if no spread to other organs is identified, capsule rupture or surface involvement increases the stage and is associated with a higher risk of recurrence.
- 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 juvenile type granulosa cell tumor, particularly in early-stage disease, but when it occurs 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 kind performed for epithelial ovarian cancers — such as BRCA mutation testing, HRD testing, or MMR testing — is not standard for juvenile type granulosa cell tumor. This is because the tumor arises through a completely different set of genetic changes and does not share the molecular vulnerabilities of carcinomas. The most clinically relevant molecular and laboratory markers are GNAS and inhibin.
GNAS mutations
Mutations in the GNAS gene are found in approximately 30% of juvenile type granulosa cell tumors. GNAS encodes a protein that acts as a signaling switch inside cells, passing messages from the cell surface to the cell’s interior. When GNAS is mutated, this switch is locked in the “on” position, leading to abnormal cell growth. GNAS mutation testing is not routinely performed at diagnosis but may be carried out as part of broader molecular profiling — for example, in cases where the diagnosis is uncertain, in recurrent disease, or when participation in a clinical trial is being considered. Results are reported as mutated or wild-type (normal).
Inhibin (serum marker)
Inhibin is a hormone normally produced by granulosa cells in the ovary. Because juvenile type granulosa cell tumors arise from granulosa cells, they often produce elevated levels of inhibin that can be detected in the blood. Serum inhibin is not typically reported in the pathology report itself — it is measured by a blood test ordered by the treating physician. However, it is included here because it is one of the most useful tools for monitoring this tumor over time. After successful surgery, inhibin levels should fall. A rise in inhibin during follow-up can be an early signal of tumor recurrence, often detectable before any abnormality is visible on imaging. Estradiol (estrogen) levels in the blood serve a similar monitoring role.
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. Juvenile 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 juvenile type granulosa cell tumors are diagnosed at stage I, which is associated with an excellent prognosis.
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 juvenile type granulosa cell tumor is generally excellent, particularly because the large majority of cases are diagnosed at stage I when the tumor is still confined to the ovary. Overall five-year survival rates exceed 90% for stage I disease. Unlike most cancers, which are primarily judged on five-year survival, juvenile type granulosa cell tumor tends to recur early — most recurrences happen within the first three years after diagnosis — and late recurrence beyond five years is uncommon. This is an important distinction from the adult type granulosa cell tumor, which is well known for very late recurrences occurring decades after initial treatment.
Factors associated with a higher risk of recurrence or worse outcomes include:
- Advanced stage — Spread beyond the ovary at diagnosis is the single most important adverse prognostic factor.
- Capsule rupture — Rupture of the ovarian capsule before or during surgery is associated with increased risk of recurrence even in stage I disease.
- Residual disease after surgery — The ability to remove all visible tumor at surgery is strongly associated with better outcomes.
- Bilateral involvement — Tumor in both ovaries at diagnosis is uncommon but associated with a higher stage.
- High mitotic activity — A very high number of dividing cells may be associated with more aggressive behavior in some cases.
What happens after the diagnosis?
Treatment is planned by a multidisciplinary team that typically includes a gynecologic oncologist, a medical oncologist and for younger patients, a pediatric oncologist. The approach depends on the patient’s age, stage, and whether fertility preservation is a priority.
Surgery is the primary treatment. Because most cases are diagnosed at stage I and occur in young patients, fertility-sparing surgery — removing only the affected ovary and fallopian tube while leaving the uterus and the other ovary in place — is the preferred approach for unilateral stage IA disease. This allows patients to retain their fertility and avoid premature menopause. For more advanced disease, or in patients who have completed childbearing, more extensive surgery may be recommended.
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 other high-risk features, chemotherapy is recommended after surgery. The most commonly used regimen is BEP (bleomycin, etoposide, and cisplatin), which is the standard chemotherapy for ovarian sex cord-stromal tumors. Radiation therapy is used in selected cases of recurrent or localized residual disease.
Long-term follow-up is essential. Because recurrence can occur — most often within the first three years — regular surveillance, including clinical examination, serum inhibin and estradiol monitoring, and imaging, is continued for several years after treatment. A rising inhibin level is often the earliest sign of recurrence and should prompt further evaluation.
For prepubertal girls in whom the tumor caused precocious puberty, the hormonal effects typically resolve after the tumor is removed. The treating team — including a pediatric endocrinologist — will monitor hormonal recovery and pubertal development after surgery.
Questions to ask your doctor
- What stage is the tumor, and what does that mean for treatment and prognosis?
- Was the tumor confined to one ovary, and was the capsule intact?
- Was fertility-sparing surgery performed, and is fertility preservation still possible?
- Were the other ovary, the uterus, and the fallopian tube examined, and were they normal?
- Did the tumor spread to the peritoneum, omentum, or lymph nodes?
- Is chemotherapy recommended, and if so, which regimen?
- What serum markers (inhibin, estradiol) should be monitored during follow-up, and at what intervals?
- What imaging schedule do you recommend for surveillance after treatment?
- What signs or symptoms of recurrence should I watch for, and how quickly should I contact the team if they occur?
- For prepubertal patients: when should we expect normal pubertal development to resume, and who will monitor hormonal recovery?
- Is this tumor associated with any inherited condition that might affect other family members?
Related articles
We are proud to partner with:
