What is the texture and appropriate management of a salivary gland tumor?

Salivary Gland Tumor Texture and Management

Salivary gland tumors typically present as firm, well-defined masses rather than soft and spongy lesions; malignant tumors may feel hard and fixed, while benign tumors are usually mobile and rubbery, though texture alone cannot reliably distinguish benign from malignant disease.

Clinical Presentation and Physical Characteristics

Painless swelling of a salivary gland should always be considered suspicious, especially if no signs of inflammation are present. 1 The texture and consistency of salivary gland masses vary:

• Malignant tumors tend to present as hard, fixed masses that may be woody in consistency, particularly when there is infiltration of surrounding structures 1
• Benign tumors are typically firm but mobile, with a rubbery consistency rather than soft and spongy 2
• Signs and symptoms differ between major and minor salivary gland tumors based on anatomical location 1

Diagnostic Evaluation Algorithm

Initial Assessment

For superficial parotid and submandibular gland lesions, ultrasound is the ideal initial imaging tool, providing excellent resolution and tissue characterization without radiation hazard. 3

Advanced Imaging Based on Clinical Suspicion

When malignancy is suspected or confirmed, proceed systematically:

• CT with IV contrast should be performed when there is suspicion of adjacent bone involvement (temporal bone, skull base, mandible, or palate), as it better evaluates bone erosion and invasion 4, 5
• Contrast-enhanced MRI with diffusion sequence should be performed when there is concern for perineural invasion and/or skull base involvement, as MRI offers superior soft tissue characterization and detection of intracranial extension 4
• PET/CT from skull base to mid-thighs may be performed for advanced-stage high-grade salivary gland cancers 4

Tissue Diagnosis

Fine needle aspiration biopsy (FNAB) is the first-line diagnostic approach, with pathologists reporting risk of malignancy using the Milan System for Reporting Salivary Gland Cytopathology. 4, 6

• Core needle biopsy (CNB) may be performed if FNAB is inadequate or the subsite precludes FNAB (such as deep minor salivary glands), with CNB showing 94% sensitivity and 98% specificity 4
• CNB has a lower inadequacy rate (1.2%) compared to FNAB (8%) 4
• Ancillary testing (immunohistochemistry or molecular studies) may be performed on biopsy specimens to support diagnosis 4, 6, 5

Risk Stratification by Location

The smaller the involved salivary gland, the higher the possibility of malignancy—this is a critical clinical principle. 3

• Parotid gland: 70-80% of all salivary gland tumors occur here, with the majority being benign; however, 15-30% harbor malignancy 7
• Submandibular gland: Nearly half of submandibular masses are malignant, warranting high suspicion and thorough preoperative evaluation 7
• Minor salivary glands: Almost all minor salivary gland tumors are malignant, requiring MRI evaluation due to high malignancy risk 3, 2

Surgical Management

Surgery with adequate free margins is the principal treatment for resectable salivary gland cancer in the absence of distant metastases. 4

Extent of Resection

• For T1-T2 low-grade superficial parotid tumors: Partial superficial parotidectomy is appropriate, with complete excision and preservation of uninvolved parotid tissue 4, 6
• For high-grade or advanced (T3-T4) tumors: At least superficial parotidectomy with consideration of total/subtotal parotidectomy is recommended due to risk of intraparotid nodal metastases 6
• Facial nerve preservation is recommended when preoperative function is intact and a dissection plane can be created between tumor and nerve 6

Intraoperative Decision-Making

Intraoperative frozen section has 98.5% sensitivity and 99% specificity for detecting malignant parotid tumors, but decisions resulting in major harm (such as facial nerve sacrifice) should not be based on indeterminate preoperative or intraoperative diagnoses alone. 4, 6

Margin Considerations

• Complete excision with adequate free margins (≥5 mm) is the goal for malignant tumors 8
• Early-stage low- and intermediate-grade parotid cancers show excellent disease control with complete surgical resection, even with narrow margins (≤5 mm), in the absence of adverse features 4, 6

Adjuvant Treatment

Adjuvant external radiation is indicated for malignant tumors with high-risk features including close or invaded margins, perineural spread, lymphatic/vascular invasion, lymph node involvement, and high-grade histology. 8

Common Pitfalls to Avoid

• Do not rely on texture alone to distinguish benign from malignant disease—tissue diagnosis is mandatory 3, 9
• Do not perform facial nerve resection based solely on indeterminate frozen section results 4, 6
• Do not underestimate submandibular and minor salivary gland masses—these have significantly higher malignancy rates than parotid masses 7, 2
• Do not skip imaging when malignancy is suspected—ultrasound alone is insufficient for deep tissue extension or skull base involvement 4, 3