Benign Tumors of Minor Salivary Glands Clinical Presentation

Updated: Jun 19, 2015
  • Author: Fadi Chahin, MD; Chief Editor: John Geibel, MD, DSc, MSc, AGAF  more...
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Presentation

History and Physical Examination

Salivary gland tumors (SGTs) usually manifest as an enlargement of the salivary glands. The classic presentation of a benign SGT is a painless, slow-growing mass on the face (parotid), angle of the jaw (parotid tail, submandibular), or neck (submandibular) or a swelling at the floor of the mouth (sublingual). A sudden increase in size may be indicative of infection, cystic degeneration, hemorrhage inside the mass, or malignant degeneration. Benign SGTs are almost always freely mobile, and for masses that arise in the parotid gland, facial nerve function should be normal. [6]

Because of the multiple and varied sites of minor salivary glands, the presentation of benign tumors in these sites may be less specific. For example, bleeding and airway compromise may be the first signs of minor SGTs of the nasal septum, whereas tumors of the base of tongue may present with dysphagia and a globus sensation. The authors have each observed one patient treated for a pleomorphic adenoma of the nasal septum and the base of the tongue. Benign tumors of the parapharyngeal space (one of which is seen in the image below) may present as trismus. Differentiating a benign, space occupying lesion from one that is truly invading the masseter and pterygoid musculature is important.

Coronal magnetic resonance imaging (MRI) scan demo Coronal magnetic resonance imaging (MRI) scan demonstrating a large, benign lesion of the parapharyngeal space.

Rule out signs of a malignant lesion, such as new onset of pain, facial nerve weakness, rapid growth, paresthesias, hoarseness, skin involvement, a fixed lesion, and cervical lymphadenopathy. Investigate weight loss, underlying infectious processes (eg, chest pain, cough, lymphadenopathy), and clinical indications of lymphoma–type B symptoms (eg, night sweats, fever).

Tumors of the salivary glands are classified based on their cytological, architectural, and biological characteristics. The World Health Organization classification of 1992 groups both benign and malignant tumors into epithelial and nonepithelial categories. Benign epithelial tumors include pleomorphic adenoma, Warthin tumor, monomorphic adenoma, intraductal papilloma (IDP), oncocytoma, and sebaceous neoplasms. Benign nonepithelial tumors (mesenchymal origin) include hemangioma, angioma, lymphangioma (cystic hygroma), lipoma, and neural sheath tumors.

An additional category of tumorlike lesions includes necrotizing sialometaplasia, benign lymphoepithelial lesions, cystic lymphoid hyperplasia (in persons with AIDS), and salivary gland cysts.

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Tumor Types

Benign epithelial tumors

Pleomorphic adenoma

Pleomorphic adenomas (benign mixed tumors) are the most common tumors of the salivary gland and are most often located in the tail of the parotid gland. When found in the minor salivary glands, the hard palate is the site most frequently involved, followed by the upper lip.

These tumors were termed pleomorphic because of the epithelial and connective tissue components that compose them in varying degrees. Their gross appearance is a round, smooth mass with a thin, delicate, incomplete capsule. Of note, pleomorphic adenomas that arise in the minor salivary glands usually lack a capsule. These tumors grow slowly, although they may become larger than other SGTs. The thin, delicate capsule may have projections into the surrounding parotid tissue. This is of particular clinical significance because obtaining clean margins and avoiding spillage are mandatory to minimize recurrence.

Treatment of benign neoplasms involves the complete surgical excision of the affected gland. If the parotid gland is involved, superficial parotidectomy with standard facial nerve dissection and preservation is the procedure of choice. Enucleation is contraindicated because of the tendency toward tumor spillage that can lead to tumor recurrence.

Warthin tumor (ie, papillary cystadenoma lymphomatosum, cystic papillary adenoma, adenolymphoma)

Albrecht first recognized this tumor in 1910, and Warthin later described it in 1929. In gross appearance, it is a smooth, soft, parotid mass. It is well encapsulated when located in the parotid gland and contains multiple cysts. Malignant transformation has not been observed. All patients with this tumor survive, and the recurrence rate is 5%. The Warthin tumor tends to be bilateral (10% of cases) and is usually found in the major glands, as are most other types.

Intraductal papilloma

Intraductal papilloma (IDP) is a small, tan, fairly smooth lesion that is usually found in the submucosal layer. IDP of the minor salivary gland is a rare lesion that has been described only in various case reports.

Oxyphil adenoma (oncocytoma)

Duplay first described the oncocytic tumor in 1875. Oncocytomas of the salivary glands are very uncommon. They rarely, if ever, occur in the minor salivary glands. Such neoplasms occur more often in women than in men, with a female-to-male ratio of 2:1. Patients are older than 50 years, and the superficial lobe of the parotid gland is the most commonly reported location. Oncocytomas manifest as small (< 5 cm in diameter), firm, slow-growing, spherical masses. Bilateral oncocytomas of the parotid glands have been described. These tumors recur if excision is incomplete. [7]

Benign nonepithelial tumors

Hemangiomas

Hemangiomas are the most common SGTs in children and usually involve the parotid gland. Less often, they may involve the submandibular gland. These vascular tumors may be distinguished from vascular malformations by their presence early in life, rapid growth phase in children aged approximately 1-6 months, and gradual involution over 1-12 years. The typical presentation is an asymptomatic, unilateral, compressible mass. Gross examination reveals a dark red, lobulated, unencapsulated mass.

Treatment should initially consist of steroids administered 2-4 mg/kg/d. Although the response may be immediate, only 40-60% of hemangiomas exhibit a response to steroids. Despite the tendency toward spontaneous involution, specific conditions may warrant surgical excision.

Lymphangioma (cystic hygroma)

Lymphangiomas are most commonly located in the head and neck region of infants and children. They are believed to be due to lymphatic sequestration of primitive embryonic lymph ducts that undergo irregular growth and canalization. They are spongy, multiloculated masses with a yellowish or bluish surface and are formed by endothelial-lined spaces. More than 50% manifest at birth, and 80% manifest by age 2 years. Usually, they manifest as painless masses that may involve parotid glands, submandibular glands, or both. Diagnosis is made based on clinical findings. Surgical excision with preservation of the vital structures is the treatment of choice. Lymphangiomas rarely cause symptoms of airway obstruction, and excision is usually for cosmetic reasons.

Lipoma

Lipoma tumors are relatively uncommon in a major salivary gland. They derive from fat cells and appear grossly as smooth, well-demarcated, bright-yellow masses. These tumors manifest as soft, mobile, painful masses and peak in the fifth and sixth decades of life, with a male-to-female ratio of 10:1. They are slow-growing tumors with an average diameter of 3 cm. Treatment is surgical excision.

Tumorlike lesions

Necrotizing sialometaplasia

Necrotizing sialometaplasia may easily be mistaken for a malignant tumor because it presents as a single, unilateral, painless or slightly painful lesion on the hard palate. However, it is a benign, self-healing lesion of the minor salivary glands that is seen in adults older than 40 years and is 2-3 times more common in men than in women. Although the etiology is unknown, it may represent a reparative process in response to ischemic necrosis of salivary tissue. A biopsy helps to rule out a malignant process; otherwise, no treatment is indicated.

Lymphoepithelial hyperplasia (Mikulicz disease, sicca complex, chronic punctate sialadenitis)

This disorder can manifest as a diffuse enlargement of all or part of the parotid gland, or it may manifest as a discrete mass. Lymphoepithelial hyperplasia is more frequent in females than in males, and its peak incidence is in the fourth and fifth decades of life. Occasionally, both parotid glands are involved. The growth of this tumor is slowly progressive, and it gives rise to pain around the ear or the retromandibular area.

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