Embryonal Carcinoma of the Testis: Understanding Your Pathology Report

Section Editor: Trevor Flood MD FRCPC
October 22, 2026

Embryonal carcinoma is a type of cancer that starts in the testicle. It belongs to a group of cancers called germ cell tumors, which develop from the cells that normally produce sperm. Embryonal carcinoma is one of the nonseminomatous germ cell tumors, often shortened to nonseminomas. It tends to grow faster and spread earlier than seminoma, but it is still very often curable.

Embryonal carcinoma is usually found mixed with other germ cell tumor types rather than alone. This article explains what embryonal carcinoma is, how the diagnosis is made, and what the findings in your embryonal carcinoma pathology report mean. It also explains why the amount of embryonal carcinoma and the presence of lymphovascular invasion matter for the next steps in your care.

Who gets embryonal carcinoma?

Embryonal carcinoma most often affects young men between 20 and 35 years old. That is about ten years younger than the typical age for seminoma. A tumor made only of embryonal carcinoma is uncommon, making up fewer than 1 in 10 testicular germ cell tumors. However, embryonal carcinoma is part of most mixed germ cell tumors.

What causes embryonal carcinoma?

Embryonal carcinoma 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 into the surrounding tissue, they can form an invasive germ cell tumor such as embryonal carcinoma.

GCNIS is thought to begin before birth, while the testicles are developing. Why it later turns into cancer in some men is not fully understood. Factors that increase the risk of testicular germ cell tumors, including embryonal carcinoma, 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 embryonal carcinoma?

The most common symptom of embryonal carcinoma 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. Because embryonal carcinoma tends to spread early, some men first notice symptoms from spread. These can include back pain from enlarged lymph nodes in the abdomen, or a cough or shortness of breath from spread to the lungs.

How is the diagnosis made?

The diagnosis of embryonal carcinoma 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. Embryonal carcinoma consists of large, highly abnormal tumor cells with large nuclei. The cells may grow in solid sheets or form gland-like spaces or finger-like papillary structures. Many dividing cells, called mitotic figures, are usually seen. Areas of dead tumor tissue, called necrosis, are also common.

The pathologist examines the entire tumor for other types of germ cell tumor. These include seminoma, yolk sac tumor, teratoma, and choriocarcinoma. If only embryonal carcinoma is present, the diagnosis is pure embryonal carcinoma. When other types are present, the diagnosis is a mixed germ cell tumor, and the report lists each type with its approximate percentage.

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 have used special stains to confirm the diagnosis, which are described in the next section.

Immunohistochemistry

Immunohistochemistry uses antibodies to show which proteins tumor cells make. In embryonal carcinoma, pathologists use immunohistochemistry to confirm the diagnosis and to separate it from seminoma and yolk sac tumor. This matters because seminoma is treated differently from embryonal carcinoma. The stains used vary between laboratories, but typical results in embryonal carcinoma include:

OCT3/4. Embryonal carcinoma cells are OCT3/4 positive. This protein is found in embryonal carcinoma and seminoma, two closely related germ cell tumors.
SALL4. Embryonal carcinoma cells are SALL4-positive. This protein is found in almost all germ cell tumors and helps confirm that the tumor started from germ cells.
CD30. Embryonal carcinoma cells are usually CD30-positive. A positive result is one of the most useful ways to separate embryonal carcinoma from seminoma.
Keratins. Embryonal carcinoma cells are usually strongly positive for keratins, while seminoma cells are usually negative or only weakly positive.
CD117 and D2-40. Embryonal carcinoma cells are usually negative for these proteins. Positive staining suggests seminoma.
AFP and glypican-3. Embryonal carcinoma cells are usually negative for these proteins. Positive staining suggests a yolk sac tumor.

Not every tumor needs all these stains, and when the diagnosis is clear under the microscope, pathologists may use only a few.

Blood tumor markers (AFP, hCG, and LDH)

Tumor markers are substances in the blood that some germ cell tumors release. For embryonal carcinoma and other testicular germ cell tumors, clinicians test three markers: alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and lactate dehydrogenase (LDH). We measure them before orchiectomy and again after. These results are reported separately from the pathology report but are interpreted alongside it.

AFP. Pure embryonal carcinoma usually makes little or no AFP. A high AFP level usually comes from a yolk sac tumor component, which is common in mixed germ cell tumors.
hCG. A mild rise in hCG can occur with embryonal carcinoma. A very high level suggests a choriocarcinoma component.
LDH. LDH is not specific to any germ cell tumor. A raised level usually reflects a larger tumor burden.

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.

Percentage of embryonal carcinoma

When embryonal carcinoma is part of a mixed germ cell tumor, your pathology report will list the approximate percentage of the tumor made up of embryonal carcinoma. The report also lists the percentage of each other type, such as seminoma, yolk sac tumor, or teratoma.

The percentage of embryonal carcinoma matters because this component tends to spread early. Several studies have linked a large amount of embryonal carcinoma with a higher chance of relapse. This applies to tumors that are limited to the testicle and treated with surgery alone. Your care team may consider this percentage, together with lymphovascular invasion, when discussing options after surgery.

Histologic grade

Unlike many other cancers, embryonal carcinoma 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. Embryonal carcinoma cells always look very abnormal so that grading adds no useful information. Your embryonal carcinoma pathology report will not include a grade, as expected.

Tumor size

The pathologist measures the embryonal carcinoma or 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.

Unlike seminoma, the tumor stage of embryonal carcinoma does not depend on size. 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 embryonal carcinoma 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 of these structures 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. Invasion of the hilar soft tissue has also been linked with a higher chance of the cancer coming back.

Lymphovascular invasion

Lymphovascular invasion means embryonal carcinoma cells 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 an embryonal carcinoma 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 embryonal carcinoma and most other testicular germ cell tumors develop. In GCNIS, abnormal germ cells line the seminiferous tubules but have not broken out into the surrounding tissue. GCNIS is often found in the testicle next to embryonal carcinoma.

Your report may mention GCNIS in the tissue around the tumor. This is expected and does not change the stage, because the invasive tumor alreadydeterminess the stage. If GCNIS is the only change found in a testicle, stage it as 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 embryonal carcinoma 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 for embryonal carcinoma, 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. Embryonal carcinoma 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 embryonal carcinoma or another active cancer means some cancer survived treatment, and your care team will consider further treatment.

Pathologic stage (pTNM)

The pathologic stage of embryonal carcinoma 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 seminoma, pT1 is not divided into pT1a and pT1b.
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 for embryonal carcinoma does not match the pathologic stage in 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 raised 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 embryonal carcinoma 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 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 embryonal carcinoma and other nonseminomas that have 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 embryonal carcinoma 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.
Positive margin. Tumor at the spermatic cord margin means some cancer may remain.

What happens after the diagnosis?

After embryonal carcinoma is confirmed on the orchiectomy specimen, the next steps depend mainly on the stage group and the 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 stage I embryonal carcinoma or 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 embryonal carcinoma 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 important because the mass may contain teratoma or active cancer even when the tumor markers are normal.

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

Is my tumor a pure embryonal carcinoma or a mixed germ cell tumor?
If it is mixed, what percentage is embryonal carcinoma, and what are the other types?
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?
Have my tumor markers returned to normal since surgery?
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?
If I need chemotherapy, which IGCCCG prognosis group am I in?
Should I bank sperm before any further treatment?
How often will I need scans and blood tests, and for how long?