Salivary Gland Tumors: Not All Lumps Are Cancer

Discovering a lump near your jaw, just in front of your ear, or beneath your chin is understandably alarming. Most people who come to see me with a swelling in or around the salivary glands assume the worst. The reality is more reassuring than you might expect: the majority of salivary gland tumors are benign. But benign does not mean harmless, and it does not mean ignore it. These tumors require proper evaluation, accurate diagnosis, and in most cases, surgical removal. Understanding what you're dealing with — and why the evaluation matters — makes a real difference in how patients experience this process.

The Salivary Glands and Where Tumors Arise

You have three pairs of major salivary glands: the parotid glands, which sit just in front of and below each ear; the submandibular glands, located beneath the jaw on each side; and the sublingual glands, which run along the floor of the mouth under the tongue. You also have hundreds of minor salivary glands scattered throughout the lining of your mouth, throat, and sinuses.

The parotid gland is by far the most common site for salivary gland tumors, accounting for roughly 70 to 80 percent of cases. Of those, approximately 80 percent are benign. The submandibular gland is the next most frequent location, but here the proportion of malignant tumors is higher — closer to 50 percent. Minor salivary gland tumors, while less common in absolute numbers, are more frequently malignant than parotid tumors. This inverse relationship between gland size and malignancy risk is a useful clinical rule of thumb: the smaller and more obscure the gland of origin, the more likely the tumor is to be cancer.

The most common benign salivary gland tumor is the pleomorphic adenoma, a slow-growing mass that can occur at any age and tends to feel firm and well-defined. The second most common is the Warthin tumor, which arises almost exclusively in the parotid gland, is more common in older men, and has a well-established association with tobacco use. Malignant tumors include mucoepidermoid carcinoma, adenoid cystic carcinoma, acinic cell carcinoma, and several rarer types. Each has a distinct behavior, degree of aggressiveness, and prognosis.

How These Tumors Present and How They're Found

Most patients notice a painless lump that has been there for months or even years before they come in. Slow growth is the norm for benign tumors — some pleomorphic adenomas expand gradually over a decade before prompting evaluation. Rapid growth, pain, facial weakness, or skin changes over the lump are features that raise concern for malignancy and warrant urgent attention.

Facial nerve weakness is a particularly important finding. The facial nerve passes directly through the parotid gland, branching into the muscles that control expression on one side of the face. A benign parotid tumor almost never causes facial weakness; when weakness is present, it usually indicates a malignant tumor invading the nerve. This is not a common presentation, but it is one that requires immediate evaluation.

When I see a patient with a salivary gland mass, the evaluation typically includes a detailed physical examination of the face and neck, followed by imaging. An MRI of the head and neck provides excellent soft tissue detail for parotid tumors. CT scan with contrast is also useful, and becuase it is relatively common, quicker and easier to obtain most patients have this study done even prior to seeing me. Ultrasound is also often used for salivary gland masses and can guide a needle biopsy when needed.

Fine needle aspiration (FNA) biopsy — a brief office procedure using a thin needle to sample cells from the tumor — is an important diagnostic step, though its accuracy for salivary gland tumors is somewhat limited compared to other head and neck sites. A skilled cytopathologist can often distinguish benign from malignant in broad terms, but the final diagnosis typically requires the entire surgical specimen.

Why Benign Tumors Still Need Surgery

A question I hear often is: "If it's probably benign, why do I need surgery?" The answer comes down to several considerations.

First, even the most reassuring imaging and biopsy results cannot tell us with certainty that a tumor is benign until the whole specimen is removed and examined by pathology. Second, benign pleomorphic adenomas carry a meaningful risk of malignant transformation over time — approximately 1.5 to 2 percent per year for long-standing tumors, which accumulates to a significant lifetime risk if the tumor is left in place for decades. Third, benign tumors don't remain benign in size indefinitely. A pleomorphic adenoma left untreated could eventually grow large enough to make surgery more complex and risky.

Surgery also provides definitive treatment. For most benign parotid tumors, a well-performed parotidectomy is curative. Recurrence rates after complete resection are low, and patients go on to live without further concern about the tumor.

What Parotid Surgery Involves

The procedure to remove a parotid tumor is called a parotidectomy. It requires careful dissection around the facial nerve — the nerve that controls the muscles of facial expression on that side — which runs directly through the gland. Protecting the facial nerve is the central technical challenge of this operation.

For most benign tumors, I perform a superficial or partial parotidectomy, removing the portion of the gland where the tumor sits while identifying and preserving every branch of the facial nerve. For tumors deep to the nerve, a total parotidectomy is sometimes necessary, requiring more extensive dissection. In cases of malignancy, the extent of resection depends on the tumor's behavior and proximity to the nerve. Nerve-sparing surgery is the goal whenever oncologically appropriate; if the nerve must be sacrificed, reconstruction using nerve grafts or reanimation techniques is an important part of the overall care plan.

After parotid surgery, patients typically go home the same day or after one night in the hospital. Temporary facial weakness can occur even when the nerve is fully intact — swelling and surgical handling can cause a temporary slowing of nerve function that resolves over weeks to months. Permanent facial nerve weakness from a skilled parotidectomy for benign disease is uncommon, though patients should understand the risk and discuss it in detail before proceeding.

One other side effect worth mentioning is Frey syndrome — redness and sweating of the cheek skin during eating, caused by regrowth of nerve fibers after surgery. It's more of an annoyance than a serious problem, and many patients don't experience it, but it's worth knowing about in advance.

Submandibular and Minor Salivary Gland Tumors

Surgery for submandibular gland tumors typically involves removal of the entire gland, a procedure called a submandibular gland excision. The anatomy in this area includes the marginal mandibular branch of the facial nerve, the lingual nerve (which carries sensation to the tongue), and the hypoglossal nerve (which controls tongue movement). A careful, deliberate dissection protects all three while fully removing the gland.

Minor salivary gland tumors of the mouth and throat are managed based on their location and pathology. Many low-grade tumors in the oral cavity can be excised through the mouth with good margins. Tumors in the palate, base of tongue, or tonsil region may require more complex resection, and some — particularly adenoid cystic carcinoma, which has a strong tendency for perineural spread and late recurrence — require radiation therapy after surgery.

When to Come In

If you've noticed a lump near your ear, jaw, or under your chin that has been there for more than a few weeks, or if you're experiencing pain or any change in facial movement, don't wait. These findings deserve a timely evaluation. Most of the time, the news is reassuring — but the evaluation itself matters, and the right workup leads to better outcomes regardless of what the tumor turns out to be.

At Aurora St. Luke's, I evaluate and operate on salivary gland tumors regularly as part of a comprehensive head and neck oncology program. If you'd like to schedule a consultation, call 414-649-3920.

Dr. Steven Sperry is a fellowship-trained head and neck surgeon specializing in head and neck cancer surgery and microvascular free flap reconstruction at Aurora St. Luke's Medical Center in Milwaukee, Wisconsin.