Pleomorphic Adenoma

Pleomorphic adenoma is a usually benign tumor that develops in a salivary gland. It most often affects the parotid gland, which sits near the ear and extends toward the jaw and cheek. The tumor may appear as a slow-growing, painless lump. The word “pleomorphic” refers to the varied appearance of its cells and tissue under a microscope; it does not by itself mean the tumor is cancerous.

Pleomorphic adenoma develops when salivary-gland epithelial and myoepithelial cells grow abnormally and form a tumor. The precise cause is often unknown. It is not generally caused by an infection or by something a person did, and most people cannot identify a preventable trigger.

What does “pleomorphic” mean?

Pleomorphic means “having many forms.” In a pleomorphic adenoma, different cell shapes and tissue patterns can appear within the same tumor when examined under a microscope. This microscopic variation helps describe the tumor’s appearance and does not, by itself, indicate cancer.

Most people with pleomorphic adenoma do not have an identifiable preventable cause. Risk factors should not be used to assign blame, and having one does not mean a tumor will develop.

A clinician examines the lump and checks facial-nerve function, including movement and sensation when appropriate. Ultrasound, MRI, or CT can help show the tumor’s location, size, and relationship to nearby structures. Imaging is especially useful for planning treatment and assessing a parotid tumor pleomorphic adenoma.

How tissue sampling helps

Fine-needle aspiration or a core biopsy may collect cells or tissue for cytology and pathology. Specialists look for the characteristic mixed microscopic appearance, including pleomorphic cells and different tissue patterns. The final diagnosis may depend on examining the removed tumor, and pathology helps distinguish pleomorphic adenoma from other salivary-gland tumors.

When observation may be considered

Careful observation may be considered in selected people with a small, stable tumor or significant medical problems that make surgery less suitable. This approach requires specialist follow-up and is not the same as monitoring a lump on your own. For a resectable pleomorphic adenoma, surgery is commonly recommended because it can remove the tumor and reduce the risk of continued growth.

Surgery and follow-up

The operation is tailored to the gland and tumor location. For a parotid tumor, appropriate parotidectomy may involve removing part or all of the affected gland while carefully identifying and preserving the facial nerve when possible. Recovery may include wound care, facial-nerve monitoring, pathology review, and surveillance visits to check for recurrence.

The outlook is generally very good because pleomorphic adenoma is usually benign and often curable with complete removal. Prognosis depends on the tumor’s size and location, whether it has returned, the pathology results, and the treatment used. Follow-up remains important because some tumors can recur, particularly after incomplete removal.