Mixed Germ Cell Tumour of the Testis: Understanding Your Pathology Report

Section Editor: Trevor Flood MD FRCPC
October 23, 2026

A mixed germ cell tumor is a type of cancer that starts in the testicle and includes two or more types of germ cell tumor. Germ cell tumors develop from the cells that normally go on to make sperm. Mixed germ cell tumor is the most common type of nonseminomatous germ cell tumor, often shortened to nonseminoma. Even when it has spread, mixed germ cell tumor are often curable.

This article explains which types of germ cell tumor can be found in a mixed germ cell tumor and how doctors make the diagnosis. It also explains what the findings in a mixed germ cell tumor pathology report mean. The percentage of each type and whether lymphovascular invasion is present are especially important for the next steps in your care.

Who gets mixed germ cell tumor?

Mixed germ cell tumor most often affects young men between 15 and 35 years old. It is one of the most common cancers in men of this age. Mixed germ cell tumor is rare after age 50. In babies and young children, testicular germ cell tumors are a different group and only rarely contain more than one type.

What causes mixed germ cell tumor?

Mixed germ cell tumor develops from an early change in the testicle called germ cell neoplasia in situ, or GCNIS. In GCNIS, abnormal germ cells grow inside the seminiferous tubules, the small tubes of the testicle where sperm are made. When these abnormal cells break out of the tubules, they can develop into several types of germ cell tumor at once. GCNIS is thought to begin before birth, while the testicles are developing. Factors that increase the risk of a testicular germ cell tumor include:

An undescended testicle. A testicle that did not descend into the scrotum in early childhood carries a higher risk, even after surgical correction.
A previous testicular cancer. Men who have had a germ cell tumor in one testicle have a small risk of a new tumor in the other.
Family history. The risk is higher when a father or brother has had testicular cancer.
Problems with testicular development. Small testicles and reduced fertility are linked with a higher risk.

What are the symptoms of mixed germ cell tumor?

The most common symptom of a mixed germ cell tumor is a lump or swelling in one testicle, which may or may not be painful. Some men notice heaviness in the scrotum or a dull ache in the lower abdomen. Some tumors release hormones that cause breast tenderness or swelling. When the tumor has spread, symptoms can include back pain from enlarged lymph nodes or a cough or shortness of breath from spread to the lungs.

How is the diagnosis made?

The diagnosis of mixed germ cell tumor usually begins with an ultrasound of the scrotum, which shows a solid mass inside the testicle. Blood tests for tumor markers are also done before surgery, because many testicular tumors release these substances into the blood. A needle biopsy of the testicle is rarely performed. Instead, the whole testicle is removed through a cut in the groin in an operation called a radical orchiectomy. The surgery removes the testicle together with part of the spermatic cord, which carries the blood vessels and the tube for sperm.

A pathologist then examines the testicle first with the naked eye, then under the microscope. Because each germ cell tumor type can occur in different parts of the mass, the pathologist examines many samples from across the tumor. The pathologist diagnoses a mixed germ cell tumor when two or more types are found. The report lists each type and its approximate percentage of the whole tumor.

Once the diagnosis is confirmed, a CT scan of the abdomen, pelvis, and chest checks whether the cancer has spread to lymph nodes or other organs. Your pathologist may also use special stains to identify each type, as described below.

Types of germ cell tumor in a mixed germ cell tumor

A mixed germ cell tumor can contain any combination of the germ cell tumor types described below. The World Health Organization (WHO) classification of testicular tumors, 5th edition (2022), defines these types. Embryonal carcinoma is the most common type found in a mixed germ cell tumor, and choriocarcinoma is the least common.

Embryonal carcinoma. Large, very abnormal-looking cells that grow in sheets or form gland-like spaces. Embryonal carcinoma tends to spread early, so a large amount of it is linked with a higher chance of the cancer coming back.
Teratoma. Tissue that looks like the normal tissues of the body, such as skin, gut lining, cartilage, or nerve tissue. Teratoma after puberty is still a cancer that can spread. It does not respond to chemotherapy, so it must be removed by surgery wherever it is found.
Yolk sac tumor. Tumor cells that form a lacy network of small spaces and other patterns. Yolk sac tumor produces a protein called alpha-fetoprotein (AFP), which raises AFP levels in the blood.
Seminoma. Sheets of large, round cells with clear cytoplasm, separated by bands of immune cells. When seminoma is mixed with any other type, treat the tumor as a nonseminoma, not a seminoma.
Choriocarcinoma. Tumor cells that look like the cells of the placenta. Choriocarcinoma makes a hormone called hCG and tends to spread through the blood, especially to the lungs.

Rarely, a part of a teratoma develops into a different type of cancer, such as an adenocarcinoma or a sarcoma. This is called teratoma with somatic-type malignancy, and your report will name the type of cancer. It matters because this cancer does not respond to the usual germ cell tumor chemotherapy, so treatment is planned around the specific cancer type.

Percentage of each type

Your mixed germ cell tumor pathology report will list the approximate percentage of each germ cell tumor type. For example, a report may describe 60% embryonal carcinoma, 30% teratoma, and 10% yolk sac tumor. The pathologist estimates these percentages by reviewing all samples taken from the tumor.

The percentages matter for two reasons. First, several studies have linked a large amount of embryonal carcinoma with a higher chance that the cancer will come back after surgery alone. Second, the presence of teratoma affects later treatment because any teratoma that has spread must be removed surgically. Small amounts still count, so even 5% choriocarcinoma or teratoma will be listed.

Immunohistochemistry

Immunohistochemistry uses antibodies to show which proteins tumor cells make. In a mixed germ cell tumor, pathologists use immunohistochemistry to identify each germ cell tumor type in the mass. The stains used vary between laboratories, but commonly used stains include:

SALL4. Positive in almost all germ cell tumor types. A positive result helps confirm that the tumor started from germ cells.
OCT3/4. Positive in embryonal carcinoma and seminoma, and negative in the other types.
CD30. Usually positive in embryonal carcinoma and negative in seminoma, helping distinguish these two types.
CD117. Usually positive in seminoma and negative in embryonal carcinoma.
Glypican-3 and AFP. Usually positive in yolk sac tumor.
hCG. Positive in choriocarcinoma and in scattered placenta-like cells in other types.

Not every tumor needs all of these stains, and when each type is clear under the microscope, only a few may be used.

Blood tumor markers (AFP, hCG, and LDH)

Tumor markers are substances in the blood that some germ cell tumors release. For a mixed germ cell tumor, doctors test three markers: alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and lactate dehydrogenase (LDH). They are measured before orchiectomy and again after. These results are reported separately from the pathology report but are interpreted alongside it.

AFP. A raised AFP usually comes from a yolk sac tumor component. Seminoma and choriocarcinoma do not make AFP.
hCG. A raised hCG can come from choriocarcinoma or from scattered placenta-like cells in other types. A very high level usually indicates choriocarcinoma.
LDH. LDH is not specific to any germ cell tumor. A raised level usually reflects a larger tumor burden.

After surgery, AFP and hCG should fall at a predictable rate. Levels that stay high or rise suggest that cancer remains elsewhere in the body. Marker levels measured after surgery are used to assign the S category in staging, described below. Our article on tumor markers in your blood test explains these tests in more detail.

Histologic grade

Unlike many other cancers, a mixed germ cell tumor is not given a histologic grade. Grade describes how different cancer cells look from normal cells, and many other cancers use it to predict behavior. For germ cell tumors, the types present and their percentages give more useful information. Your mixed germ cell tumor pathology report will not include a grade, as expected.

Tumor size

The pathologist measures the mixed germ cell tumor in the removed testicle and reports its greatest dimension in centimeters. If there is more than one tumor nodule, the pathologist usually measures the largest and lists the others separately. For mixed germ cell tumors, size does not change the tumor stage. Some studies have found that larger tumors are more likely to come back after surgery, so size may still be considered when planning follow-up.

Tumor extension

Tumor extension describes how far the mixed germ cell tumor has grown beyond the testicle. The pathologist examines the nearby tissues to see whether tumor cells have reached any of these structures:

Rete testis. A network of small channels near the top of the testicle that collects sperm. Growth into the rete testis does not change the stage.
Hilar soft tissue. The fatty tissue at the back of the testicle, where blood vessels enter and leave.
Epididymis. The coiled tube on the back of the testicle that stores sperm.
Tunica vaginalis. The thin outer lining that covers the testicle. Growth through this lining is called perforation of the tunica vaginalis.
Spermatic cord. The cord that runs from the testicle up into the groin.
Scrotum. The skin and tissue that hold the testicles.

Growth into any structure except the rete testis increases the tumor stage (pT). Growth into the tunica albuginea, the tough capsule directly around the testicle, does not raise the stage on its own.

Lymphovascular invasion

Lymphovascular invasion means tumor cells from the mixed germ cell tumor were seen inside a blood vessel or lymphatic channel. These vessels carry blood and fluid away from the testicle, so tumor cells inside them have a route to spread. Your report will describe lymphovascular invasion as present, not identified, or cannot be determined.

Lymphovascular invasion is one of the most important findings in a mixed germ cell tumor report. It changes the stage, because a tumor limited to the testicle is pT1 without lymphovascular invasion but pT2 with it. It is also the strongest predictor of whether a nonseminoma limited to the testicle will come back after surgery alone.

Germ cell neoplasia in situ (GCNIS)

Germ cell neoplasia in situ, or GCNIS, is the early change from which a mixed germ cell tumor develops. In GCNIS, abnormal germ cells line the seminiferous tubules but have not invaded the surrounding tissue. GCNIS is often found in the testicle next to a mixed germ cell tumor. This is an expected finding and does not change the stage, because the invasive tumor already sets the stage. If GCNIS is the only change found in a testicle, it is given the stage pTis.

Scar or regressed germ cell tumor

Sometimes a germ cell tumor shrinks or disappears inside the testicle before surgery, leaving only a scar, in a process called regression. Your report may describe a scar, fibrosis, or a regressed germ cell tumor. The pathologist makes this diagnosis when the scar contains GCNIS or coarse calcifications inside the tubules. A regressed tumor matters most when a germ cell tumor has already been found elsewhere, because the scar shows the cancer most likely started in the testicle.

Surgical margins

A margin is the cut edge of tissue removed during surgery. After a radical orchiectomy, the most important margin is the end of the spermatic cord, which is the last tissue cut by the surgeon. Your report will describe the margins in one of these ways:

Negative margin. No tumor cells are seen at any cut edge, meaning the surgeon removed the tumor completely.
Positive margin. Tumor cells are present at a cut edge, usually the spermatic cord margin. This means some tumor may remain in the body, and your care team will consider whether further treatment is needed.

When only part of the testicle has been removed, in an operation called a partial orchiectomy, the report also describes the margin in the remaining testicle.

Lymph nodes

Lymph nodes are small immune organs found throughout the body. A mixed germ cell tumor usually spreads first to the retroperitoneal lymph nodes at the back of the abdomen. These nodes are not removed during a radical orchiectomy, so most orchiectomy reports do not include any lymph nodes.

A later operation called a retroperitoneal lymph node dissection may remove the retroperitoneal lymph nodes. When they are, the pathologist reports:

Number of lymph nodes. How many nodes were examined, and how many contained cancer.
Size. The size of the largest tumor deposit or the largest mass of involved nodes.
Extranodal extension. Whether cancer cells have broken through the outer capsule of a lymph node into surrounding tissue. Extranodal extension raises the nodal stage to at least pN2.
Type of tumor in the nodes. Germ cell tumor types found in the lymph nodes can differ from those in the testicle.

When lymph nodes are removed after chemotherapy, the report describes what remains. Dead tumor and scar tissue, described as necrosis and fibrosis, mean the chemotherapy worked. Teratoma means a part of the tumor that does not respond to chemotherapy remained and has now been removed. Viable germ cell tumor or a somatic-type malignancy means some cancer survived treatment, and your care team will consider further treatment.

Pathologic stage (pTNM)

The pathologic stage of a mixed germ cell tumor is based on the tumor in the removed testicle (pT) and any lymph nodes examined (pN). It uses the TNM staging system in the 8th edition of the AJCC Cancer Staging Manual, which the current CAP testis protocol uses. Spread to distant organs (M) is usually determined by imaging, not by the pathologist.

Tumor stage (pT)

pTis. Only germ cell neoplasia in situ (GCNIS) is present, with no invasive tumor.
pT1. The tumor is limited to the testicle and has no lymphovascular invasion. Growth into the rete testis or tunica albuginea remains pT1. Unlike pure seminoma, pT1 is not divided by size.
pT2. The tumor is limited to the testicle with lymphovascular invasion. A tumor that grows into the hilar soft tissue or the epididymis, or through the tunica vaginalis, is also pT2.
pT3. The tumor grows directly into the spermatic cord soft tissue.
pT4. The tumor grows into the scrotum.
pT0. No tumor is found in the testicle, a result that may be used when only a scar from a regressed tumor remains.

Sometimes tumor cells are found in the spermatic cord, separate from the main tumor, carried there in a blood vessel. Under the AJCC 8th edition, this is treated as a deposit of spread cancer and staged as pM1, not pT3. Older reports written under the 7th edition staged this finding as pT3.

Nodal stage (pN)

pN0. No cancer is found in any of the lymph nodes examined.
pN1. Cancer is found in up to 5 lymph nodes, and no node or mass of nodes is larger than 2 cm.
pN2. The largest node or mass of nodes is larger than 2 cm but not larger than 5 cm. More than 5 positive nodes, or extranodal extension, is also pN2.
pN3. A lymph node mass is larger than 5 cm.
pNX. Lymph nodes were not sent for examination, which is the usual result after a radical orchiectomy.

The overall stage group of a mixed germ cell tumor is not the same as the pathologic stage on your report. Your care team assigns the stage group by combining the pathology findings, the CT scans, and the blood tumor markers (the S category, from S0 to S3). In broad terms, the stage groups are:

Stage I. The cancer is limited to the testicle and nearby structures, with no spread to lymph nodes or distant organs. Stage IS means the scans are clear, but the tumor markers stay elevated after surgery.
Stage II. The cancer has spread to the lymph nodes at the back of the abdomen. Stages IIA, IIB, and IIC reflect the size of the involved nodes.
Stage III. The cancer has spread to distant lymph nodes or organs such as the lungs, or tumor marker levels are very high.

What is the prognosis?

The prognosis for a mixed germ cell tumor is very good for most people, even when it has spread. Testicular germ cell tumors respond well to chemotherapy that includes cisplatin, and most people with a nonseminoma are cured.

For a nonseminoma limited to the testicle, about 30 in 100 people have the cancer come back after surgery alone. Lymphovascular invasion has the biggest effect on this risk. Without it, about 15 in 100 relapse, but with it, about 50 in 100 relapse. Almost all relapses happen within two years and are usually cured with chemotherapy.

For a mixed germ cell tumor that has spread, an international system called IGCCCG places people in one of three groups. The groups are based on where the cancer has spread and how high the tumor markers are. Results from the IGCCCG update published in 2021 show:

Good prognosis. About 96 in 100 people are alive five years later, and about 90 in 100 have no further growth of the cancer.
Intermediate prognosis. About 89 in 100 people are alive five years later, and about 78 in 100 have no further growth of the cancer.
Poor prognosis. About 67 in 100 people are alive five years later, and about 54 in 100 have no further growth of the cancer.

Pathologic features on your mixed germ cell tumor report that are linked with a higher chance of the cancer spreading or coming back include:

Lymphovascular invasion. This is the strongest single predictor of relapse for tumors limited to the testicle.
A large percentage of embryonal carcinoma. Tumors made mostly of embryonal carcinoma are more likely to spread.
Hilar soft tissue invasion and larger tumor size. Both have been linked with a higher chance of relapse.
Spread beyond the testicle. Growth into the spermatic cord or scrotum raises the stage.
Teratoma with somatic-type malignancy. This rare finding behaves like the specific cancer type and does not respond to the usual germ cell tumor chemotherapy.

What happens after the diagnosis?

After confirming a mixed germ cell tumor on the orchiectomy specimen, the next steps depend mainly on the stage group and blood tumor markers. For stage I tumors, lymphovascular invasion and the percentage of embryonal carcinoma also matter. A team that includes a urologist and a medical oncologist usually plans care.

For a stage I mixed germ cell tumor, the options your team may discuss include:

Active surveillance. Regular checkups, blood tests, and CT scans, with treatment only if the cancer comes back. Current European guidelines prefer surveillance for most people without lymphovascular invasion.
One cycle of chemotherapy. A single cycle of a combination that includes cisplatin lowers the chance of relapse to about 2 or 3 in 100. It is often discussed when lymphovascular invasion is present.
Retroperitoneal lymph node dissection. Surgery to remove the lymph nodes at the back of the abdomen, done in specialized centers. It both checks for hidden spread and removes it.

For a mixed germ cell tumor that has spread, treatment usually involves chemotherapy combinations that include cisplatin, with the amount guided by the IGCCCG prognosis group. If a lymph node mass larger than 1 cm remains after chemotherapy, surgeons usually remove it. This is especially important when the testicle contains teratoma, because teratoma does not shrink with chemotherapy and can keep growing.

Removing one testicle usually does not affect fertility or hormone levels because the other testicle continues to function. Chemotherapy and lymph node surgery can affect fertility, so sperm banking is usually discussed before any further treatment. Some men choose a testicular prosthesis, which can be placed during the orchiectomy or later. Follow-up visits continue for several years and include tumor markers, scans, and checks of testosterone and of the remaining testicle.

Questions to ask your doctor

Which types of germ cell tumor were found in my tumor, and what percentage is each?
How much of my tumor is embryonal carcinoma?
Did my tumor contain teratoma, and how does that affect my treatment?
Was a somatic-type malignancy found?
Was lymphovascular invasion present?
Did the tumor grow into the hilar soft tissue, epididymis, or spermatic cord?
Was the spermatic cord margin negative?
What were my AFP, hCG, and LDH levels before and after surgery, and are they back to normal?
What is my overall stage, and how was it decided?
What is my chance of relapse with surveillance, and how would chemotherapy or surgery change it?
Should I bank sperm before any further treatment?
How often will I need scans and blood tests, and for how long?