Salivary Duct Carcinoma: Understanding Your Pathology Report

by Jason Wasserman MD PhD FRCPC
May 6, 2026

Salivary duct carcinoma is one of the most aggressive types of cancer that starts in the salivary glands — the glands that make saliva. Unlike most salivary gland cancers, it grows quickly, often spreads to lymph nodes early, and can spread to distant sites such as the lungs, bones, and liver. Under the microscope, it looks similar to a high-grade form of breast cancer called ductal carcinoma, which is why it is given the “duct” name. Although salivary duct carcinoma is a serious diagnosis, it is also one of the salivary gland cancers most likely to respond to targeted drug treatments aimed at specific changes in the tumor’s DNA. For this reason, biomarker testing is an important part of the workup, as described later in this article.

This article will help you understand the findings in your pathology report — what each term means and why it matters for your care.

What causes salivary duct carcinoma?

The cause of salivary duct carcinoma is not known in most cases. It is not strongly linked to smoking, alcohol, or any other lifestyle factor. About half of all salivary duct carcinomas arise on their own, and about half arise within a long-standing benign salivary gland tumor called a pleomorphic adenoma. When this happens, the diagnosis is called carcinoma ex pleomorphic adenoma (“ex” means “from”). The most common type of cancer to develop within a pleomorphic adenoma is salivary duct carcinoma. This is why a pleomorphic adenoma that has been stable for years and then suddenly starts to grow rapidly is taken seriously and is usually removed promptly.

At the DNA level, salivary duct carcinomas often exhibit several genetic changes that drive tumor growth. The most important of these from a treatment standpoint are described in the biomarker and molecular testing section later in this article. These genetic changes happen by chance during a person’s lifetime. They are not inherited and cannot be passed to children.

Where does salivary duct carcinoma start?

Most salivary duct carcinomas start in the parotid gland — the largest salivary gland, which sits in front of and below each ear. The parotid gland is involved in about 80% of cases. The remainder occur in the submandibular gland (under the jaw), the sublingual gland (under the tongue), or in the small minor salivary glands in the lining of the mouth and throat. Salivary duct carcinoma is much more common in men than in women — about 3 to 4 times more common — and most often occurs after age 50.

What are the symptoms of salivary duct carcinoma?

Unlike many other salivary gland cancers, salivary duct carcinoma tends to grow quickly and often produces noticeable symptoms early on:

Rapidly growing lump or swelling — A firm, fast-growing mass in the parotid or submandibular gland is the most common finding.
Pain or tenderness — Pain in the area of the tumor is common in salivary duct carcinoma and is more typical of this cancer than of other salivary gland tumors.
Facial weakness or paralysis — The facial nerve, which controls the muscles of facial expression, runs through the parotid gland. Salivary duct carcinoma frequently invades this nerve, causing weakness or paralysis of one side of the face.
Numbness — Numbness of the skin over the tumor or near the lower lip can result from the invasion of nearby nerves.
Swelling in the neck — Often caused by the spread of the tumor to nearby lymph nodes, which is common in this type of cancer.
Sudden change in a long-standing lump — A pleomorphic adenoma that has been stable for years and then suddenly begins to grow more rapidly is a warning sign of carcinoma ex pleomorphic adenoma, most often salivary duct carcinoma.

How is the diagnosis made?

The diagnosis is made after a tissue sample is examined under the microscope by a pathologist. Most patients first have an imaging test — usually an ultrasound, CT scan, or MRI — that shows a mass in the salivary gland. A fine needle aspiration biopsy (FNAB) is often done first to take a small sample of cells through a thin needle. If the FNAB does not give a clear answer, a core needle biopsy may be done instead. In many cases, the entire tumor is removed in a single operation, and the diagnosis is made on this larger sample.

Under the microscope, the pathologist looks for tumor cells arranged in solid clusters and in patterns that look very similar to a type of breast cancer called high-grade ductal carcinoma. Two patterns are especially typical:

Cribriform pattern — Large nests of cells containing many small round holes, giving a sieve-like appearance.
Papillary-cystic pattern — Finger-like projections of tumor cells extending into open spaces (cysts) within the tumor.

The cells themselves are large with pink-staining cytoplasm (the fluid inside the cell). They show marked variation in size and shape, which is one of the features that identifies this as a high-grade tumor. Visible nucleoli (small dense spots within the part of the cell that holds DNA) are common, and many mitotic figures (cells in the act of dividing) are seen. A typical finding is comedonecrosis — areas of cell death in the center of the tumor nests, which look like the comedones (plugs) inside a high-grade form of breast cancer. The tumor cells often resemble those of apocrine glands, a type of sweat gland.

Some salivary duct carcinomas contain a part of the tumor that has not yet broken out of the salivary duct, called the in situ or intraductal component. When the entire tumor is in situ and has not invaded surrounding tissue, the diagnosis becomes intraductal carcinoma — a separate, much less aggressive entity that has been recognized in its own right since 2017 (and was previously called “low-grade salivary duct carcinoma”). This article focuses on the invasive form. If a pleomorphic adenoma is found next to or surrounding the salivary duct carcinoma, the diagnosis is updated to carcinoma ex pleomorphic adenoma.

To confirm the diagnosis, the pathologist often uses immunohistochemistry, a staining technique that highlights specific proteins in tumor cells. Salivary duct carcinoma is typically positive for proteins called androgen receptor (AR), GCDFP-15, and GATA3. AR is positive in 70–95% of cases and is one of the most reliable markers for this diagnosis. About one-third of tumors are also positive for HER2. The combination of AR and GCDFP-15 staining is one of the strongest signs of salivary duct carcinoma. AR and HER2 are also important treatment targets, so they appear again in the biomarker and molecular testing section below. Once the diagnosis is confirmed, additional imaging is used to assess spread before treatment is planned.

Tumor extension (extraparenchymal extension)

Extraparenchymal extension means the tumor has spread beyond the salivary gland into surrounding tissues, such as fat, muscle, or skin. This finding is reported only for tumors that arise in one of the three major salivary glands — the parotid, submandibular, or sublingual gland. Extraparenchymal extension is common in salivary duct carcinoma because of how aggressively the tumor invades. Tumors with extraparenchymal extension are given a higher pathologic stage (pT) and are at higher risk of coming back after surgery.

Lymphovascular invasion

Lymphovascular invasion means that tumor cells have entered small blood vessels or lymphatic vessels in or near the tumor. These vessels can carry the cells to lymph nodes or to distant parts of the body. Lymphovascular invasion is found in most salivary duct carcinomas and is one of the reasons this tumor spreads so often. When found, it raises the risk that the cancer will come back and is one of the factors that leads doctors to recommend radiation therapy after surgery.

Perineural invasion

Perineural invasion means that tumor cells are growing around or along a nerve. The facial nerve, which runs through the parotid gland, is the most common nerve involved when salivary duct carcinoma starts there. Perineural invasion is very common in salivary duct carcinoma and explains the facial weakness, numbness, and pain that many patients experience. When seen on a pathology report, it raises the risk that the tumor will come back near the original site, and it is one of the reasons radiation therapy is almost always recommended after surgery.

Surgical margins

A margin is the edge of the tissue that the surgeon cuts when removing the tumor. The pathologist examines these edges under the microscope to see whether any tumor cells reach the cut surface.

Negative margin — No tumor cells are seen at the cut edge. This suggests the tumor was completely removed, and the chance of it growing back is much lower.
Close margin — Tumor cells are very close to the cut edge but do not reach it. The pathologist may report the exact distance in millimeters. A close margin can raise the risk that the tumor will come back near the original site.
Positive margin — Tumor cells are seen at the cut edge of the tissue. This means tumor cells were almost certainly left behind. A positive margin usually leads to a recommendation for either more surgery or more aggressive radiation therapy after surgery.

Margin assessment is especially difficult in parotid surgery because the surgeon must work around the facial nerve. In salivary duct carcinoma, the tumor often invades the facial nerve, and the surgeon may need to remove part of the nerve along with the tumor to achieve a clean margin.

Lymph nodes

Lymph nodes are small immune organs scattered throughout the body. The lymph nodes most likely to be involved by salivary duct carcinoma are those in the neck, particularly in the area called level II, immediately below the angle of the jaw. Spread to lymph nodes is very common in salivary duct carcinoma, occurring in around 60% of patients at the time of diagnosis. Because of this high rate, a neck dissection (removal of lymph nodes from one or both sides of the neck) is usually part of the initial operation, even when the lymph nodes look normal on imaging.

Negative lymph node — No tumor cells are found in the node.
Positive lymph node — Tumor cells are found inside the node. The report will describe how many nodes contain tumor, the size of the largest deposit, and whether the tumor has grown beyond the outer wall of the node — a feature called extranodal extension.

Both the number of involved nodes and the presence of extranodal extension are important factors in deciding how aggressive the radiation therapy after surgery should be.

Biomarker and molecular testing

A biomarker is something that can be measured in a tumor sample — most often a protein on the surface of the tumor cells or a change in the tumor’s DNA — that helps doctors predict how the tumor will behave or decide whether a treatment is likely to work. Salivary duct carcinoma is the salivary gland cancer most likely to benefit from biomarker-guided treatment. Several different types of targeted drug therapy are now available for patients whose tumor has the right biomarker profile, and biomarker testing is considered standard for any patient with advanced or recurrent disease — and is increasingly done at the time of diagnosis as well. The tests below are the ones most commonly used.

Androgen receptor (AR)

The androgen receptor is the same protein that drives the growth of prostate cancer. It is found in 70–95% of salivary duct carcinomas. Tumors that are AR positive can be treated with the same kinds of drugs that are used to treat prostate cancer — drugs that lower the level of male hormones in the body or block their effect on the tumor cells. Common options include leuprolide (which lowers male hormone levels) and bicalutamide or enzalutamide (which block the androgen receptor). This approach is called androgen deprivation therapy. AR status is assessed by immunohistochemistry on tumor tissue.

HER2 (ERBB2)

HER2 is the same protein that is targeted in HER2-positive breast cancer. About 30–45% of salivary duct carcinomas have high levels of HER2, either because the tumor cells have extra copies of the HER2 gene (gene amplification) or because the protein is overproduced. HER2-positive salivary duct carcinomas can be treated with HER2-targeted drugs such as trastuzumab, pertuzumab, ado-trastuzumab emtansine (T-DM1), and trastuzumab deruxtecan (T-DXd). Trastuzumab deruxtecan in particular has shown strong activity in HER2-positive salivary duct carcinoma. HER2 status is usually checked first by immunohistochemistry; uncertain results are confirmed with a separate test called fluorescence in situ hybridization (FISH) that examines the number of gene copies.

Other genetic changes

Several other genetic changes can also be found in salivary duct carcinoma and may guide treatment in selected cases:

PIK3CA mutations — Found in about 25–30% of tumors. Drugs that target the PIK3CA pathway (such as alpelisib) may be considered, often in combination with other treatments.
HRAS mutations — Found in about 15–20% of tumors. Tipifarnib, a drug that targets HRAS-mutated cancers, has shown activity in clinical trials.
BRAF V600E mutations — Found in a small number of tumors. BRAF inhibitor drugs such as dabrafenib (often combined with trametinib) can be highly effective in BRAF-mutated cancers.
TP53 mutations — Common in salivary duct carcinoma but not directly targeted by available drugs. Their presence has prognostic meaning rather than treatment meaning.

These genetic changes are usually identified using next-generation sequencing (NGS), a single test that can look at hundreds of genes at the same time. NGS is now considered standard for any patient with advanced or recurrent salivary duct carcinoma.

Pathologic stage (pTNM)

Pathologic staging describes the size of the tumor and how far it has spread, based on the findings at surgery. It uses the TNM system: T stands for the size and extent of the primary tumor, N stands for involvement of nearby lymph nodes, and M stands for spread to distant parts of the body. Staging applies only to salivary duct carcinomas of the major salivary glands. Tumors of the minor salivary glands are staged using the system for the area where they started (such as the oral cavity or oropharynx).

Tumor stage (pT)

T1 — The tumor is 2 cm or smaller and confined to the salivary gland.
T2 — The tumor is larger than 2 cm but not larger than 4 cm and is still confined to the salivary gland.
T3 — The tumor is larger than 4 cm, or has spread beyond the salivary gland into surrounding soft tissue (extraparenchymal extension).
T4a — The tumor has invaded skin, the jawbone, the ear canal, or the facial nerve.
T4b — The tumor has invaded the base of the skull, nearby bones, or major blood vessels.

Nodal stage (pN)

N0 — No tumor cells in any examined lymph nodes.
N1 — A single lymph node on the same side of the neck contains tumor, and is 3 cm or smaller, with no extranodal extension.
N2a — A single lymph node on the same side of the neck is between 3 and 6 cm, or any lymph node shows extranodal extension.
N2b — Multiple lymph nodes on the same side of the neck contain tumor, none larger than 6 cm, with no extranodal extension.
N2c — Lymph nodes on both sides of the neck or on the opposite side from the tumor contain tumor, none larger than 6 cm, with no extranodal extension.
N3a — A lymph node larger than 6 cm contains tumor.
N3b — Any positive lymph node shows extranodal extension (apart from the single small node category covered under N2a).

What is the prognosis?

Salivary duct carcinoma is the most aggressive of the common salivary gland cancers, and the outlook has historically been guarded. Reported outcomes include:

5-year overall survival — Approximately 40–55%.
10-year overall survival — Approximately 25–35%.
Distant spread — Roughly half of patients eventually develop spread to distant sites such as the lungs, bones, or liver.

The introduction of targeted therapies — particularly HER2-directed drugs such as trastuzumab deruxtecan and androgen deprivation therapy for AR-positive disease — has improved outcomes for patients with advanced disease over the last decade, and ongoing clinical trials continue to test new combinations.

Several features in the pathology report can identify patients at higher risk of a worse outcome:

Larger tumor size — Tumors larger than 4 cm have a higher risk of spread.
Extraparenchymal extension — Tumors that have grown beyond the salivary gland are at higher risk of recurrence.
Positive surgical margins — Incompletely removed tumors are more likely to come back.
Lymph node involvement — The number of involved nodes and the presence of extranodal extension both worsen prognosis.
Perineural and lymphovascular invasion — Both are linked with a higher risk of the tumor coming back.
Distant metastases at presentation — Patients with metastatic disease at diagnosis have a worse outlook than those with disease confined to the head and neck.

What happens after the diagnosis?

Treatment for salivary duct carcinoma is led by a head and neck surgeon. The surgeon often works with a radiation oncologist, a medical oncologist, and a speech-language pathologist for any rehabilitation needs. Treatment is more intensive than for most other salivary gland cancers because of the aggressive nature of this tumor.

Surgery — The mainstay of initial treatment. For parotid tumors, this is usually a total parotidectomy. The facial nerve is preserved when possible, but it may need to be removed in part or in full when the tumor has invaded it. Submandibular tumors are removed along with the entire affected gland.
Neck dissection — Removal of lymph nodes from one or both sides of the neck. Almost always part of the initial operation in salivary duct carcinoma because the rate of lymph node spread is so high, even when the lymph nodes look normal on imaging.
Radiation therapy after surgery — Almost always recommended in salivary duct carcinoma to lower the risk of the tumor coming back near the original site. Radiation is given as a series of daily treatments over several weeks.
Targeted drug therapy — One of the most important advances in salivary duct carcinoma treatment in the last decade. Patients with AR-positive tumors can be treated with androgen deprivation therapy (drugs that lower or block male hormones). Patients with HER2-positive tumors can be treated with HER2-targeted drugs such as trastuzumab deruxtecan. These options are described in detail in the biomarker and molecular testing section.
Standard chemotherapy — May be used in combination with targeted therapy or radiation, particularly for advanced disease. Chemotherapy alone is generally not as effective as targeted therapy for tumors that have a treatable biomarker.
Clinical trials — Many promising drugs are being tested for salivary duct carcinoma. Patients with advanced or recurrent disease should ask whether a clinical trial is available.
Long-term surveillance — Regular clinical examination of the head and neck, with imaging of the head and neck and chest, continues for many years after treatment.

Questions to ask your doctor

Where exactly did the tumor start, and how large was it?
Did the tumor develop on its own, or did it arise within a previous pleomorphic adenoma?
What is the pathologic stage (pT, pN, and overall TNM stage) of my cancer?
Was the tumor completely removed? What were the surgical margins?
If a margin was positive or close, will I need more surgery or radiation therapy?
Were perineural or lymphovascular invasion identified?
How many lymph nodes were involved by tumor, and was extranodal extension present?
Was my tumor tested for androgen receptor (AR), HER2, and other genetic changes?
If my tumor is AR positive, am I a candidate for androgen deprivation therapy?
If my tumor is HER2 positive, am I a candidate for HER2-targeted therapy such as trastuzumab deruxtecan?
Was next-generation sequencing performed, and did it identify any other targetable genetic changes (such as PIK3CA, HRAS, or BRAF)?
Will I need radiation therapy after surgery?
Will I need additional drug therapy, and which type?
What is my estimated risk of the cancer coming back or spreading?
What is the schedule for follow-up examinations and imaging, and how long will it continue?
Will I have any lasting facial weakness, numbness, or dryness of the mouth from the surgery?
Are there any clinical trials I should consider?