Initial Imaging for Jaw Mass Evaluation
Order plain radiographs (panoramic radiography/orthopantomography) as the first-line imaging study for any patient presenting with a jaw mass of unknown etiology. 1, 2, 3
Rationale for Radiographs First
Plain radiographs serve as the foundational imaging modality because they can:
- Identify critical diagnostic features in 62% of jaw masses, including calcifications, bone involvement, cortical destruction, and intrinsic fat content 2, 3
- Distinguish between radiolucent lesions (cysts, ameloblastomas, giant cell lesions) and radiopaque lesions (fibrous dysplasia, ossifying fibroma, osteomas) that guide differential diagnosis 3, 4
- Detect tooth displacement, root resorption, and periapical pathology that narrow the diagnostic possibilities 1, 4
- Provide immediate information about bone integrity before any biopsy or surgical intervention 1
When to Advance to Cross-Sectional Imaging
Order CT maxillofacial without IV contrast when radiographs show concerning features or are insufficient for treatment planning 1, 3:
- Complex anatomical involvement requiring assessment of cortical integrity, mandibular canal proximity, or maxillary sinus floor relationship 1
- Suspected malignancy based on aggressive radiographic features (ill-defined borders, cortical destruction, soft tissue extension) 3
- Preoperative planning for resection or biopsy, particularly for deep-seated lesions 5
- Evaluation of mineralization patterns that distinguish myositis ossificans from malignant ossification 1
Order MRI without and with IV contrast for specific clinical scenarios 2, 3:
- Soft tissue characterization when the mass extends significantly beyond bone into adjacent soft tissues 2, 3
- Suspected vascular lesions or when clinical examination suggests high vascularity 1, 2
- Neurogenic tumors or when there are neurological symptoms suggesting nerve involvement 1, 2
Critical Pitfalls to Avoid
Never skip radiographs and proceed directly to advanced imaging - this violates established appropriateness criteria and exposes patients to unnecessary radiation and cost 1. The ACR explicitly states that "literature does not support the use of MRI as the initial examination for a soft-tissue mass" 1.
Do not order ultrasound for jaw masses - while ultrasound has 94.1% sensitivity for superficial soft tissue masses elsewhere, its diagnostic accuracy "is considerably less when lesions outside the subcutaneous tissue are included" and it cannot adequately assess bone involvement 1, 2.
Obtain imaging before biopsy - radiographic assessment must precede tissue sampling to avoid obscuring diagnostic features with post-procedural changes and to guide biopsy site selection 1, 2.
Special Considerations
For pediatric patients, delay radiographic evaluation until age 6 unless there are compelling clinical signs (rapid growth, pain, functional impairment, or suspected malignancy), as permanent tooth buds are not adequately visible before this age 1, 6.
For suspected osteoradionecrosis in patients with prior head and neck radiation (≥50 Gy), the initial evaluation should include both clinical intraoral examination and formal radiographic examination (orthopanogram, cone-beam CT, or fan-beam CT) 1.
For trauma-related jaw masses, CT maxillofacial without IV contrast is the appropriate initial study rather than plain radiographs, as it better evaluates fracture patterns and soft tissue injury 1.