What is the best imaging approach for a buccal mass?

Imaging Approach for Buccal Mass

For a buccal mass, contrast-enhanced CT or MRI with contrast is the recommended first-line imaging modality, with MRI being preferred when there is concern for perineural invasion or skull base involvement. 1

Initial Imaging Selection Algorithm

First-Line Imaging:

• Contrast-enhanced CT of the neck/maxillofacial region

  • Advantages:
    • Superior spatial resolution 1
    • Excellent delineation of osseous anatomy 1
    • Can distinguish bony remodeling (benign) from lytic destruction (malignant) 1
    • Can identify calcifications within tumors 1
  • Best for:
    • Initial evaluation of buccal masses in adults 1
    • Cases where bone involvement is suspected 1
    • Surgical planning 1

• MRI with contrast and diffusion sequence

  • Advantages:
    • Superior soft tissue characterization 1
    • Better evaluation of perineural spread 1
    • Better assessment of intracranial extension 1
    • Diffusion-weighted imaging helps differentiate benign from malignant lesions 2
  • Best for:
    • Suspected perineural invasion 1
    • Skull base involvement 1
    • Soft tissue characterization 1
    • Determining intraparotid vs. extraparotid origin 2

Special Considerations:

• Ultrasound

  • May be used as first-line imaging tool in children 1
  • Useful for initial evaluation to differentiate extra from intraglandular masses 1
  • Limited for deep extension evaluation and skull base involvement 1
  • Can guide fine-needle aspiration biopsy 1

• PET/CT

  • Not recommended for initial evaluation 1
  • May be considered for advanced-stage high-grade salivary gland cancers 1
  • Useful for detecting regional and distant metastases in malignant cases 1

Imaging Features to Evaluate

1. Location and extent:

   • Relationship to buccinator muscle helps differentiate buccal gland tumors from epidermoid cysts and accessory parotid tumors 3
   • Determine if mass is intraparotid or extraparotid 2
   • Assess involvement of adjacent structures 4

2. Tissue characteristics:

   • Internal architecture (solid, cystic, mixed) 3, 4
   • Enhancement pattern 4
   • Presence of calcifications or phleboliths (suggestive of hemangiomas) 3

3. Signs of malignancy:

   • Ill-defined margins 3
   • Violation of fascial planes 3
   • Bone destruction 3
   • Decreased T2 signal and apparent diffusion coefficient on MRI 1

Common Pitfalls and Caveats

1. Diagnostic limitations:

   • CT has limited value in differentiating malignant from benign buccal space lesions (sensitivity only 64%) 3
   • Imaging alone often cannot provide a specific diagnosis; histologic sampling is frequently necessary 1, 5

2. Anatomical considerations:

   • Buccal space masses can be confused with masticator space pathology 6
   • Normal lymph nodes may be difficult to distinguish from facial neurovascular bundles 4

3. Most common pathologies:

   • Salivary gland tumors are the most common buccal space masses 4
   • Other possibilities include hemangiomas, dilated parotid ducts, and soft-tissue malignancies 4

Conclusion

When evaluating a buccal mass, imaging plays a crucial role in determining the extent of disease and guiding treatment planning. While ultrasound may be useful for initial assessment, contrast-enhanced CT or MRI provides more comprehensive evaluation. CT is excellent for assessing bony involvement, while MRI offers superior soft tissue characterization and is preferred when perineural invasion or skull base involvement is suspected. The choice between CT and MRI should be based on the clinical presentation and suspected pathology, with both modalities often being complementary rather than competitive.