From the Guidelines
Cystic or necrotic lesions within or adjacent to the mandibular gland should be evaluated with MRI orbits, face, and neck without and with IV contrast, as it provides superior soft tissue contrast resolution and is considered the modality of choice for initial staging of major salivary gland cancer. These lesions may represent several conditions including salivary gland tumors (benign or malignant), ranulas, mucoceles, or inflammatory processes. The use of MRI is supported by a recent study published in the Journal of the American College of Radiology in 2023 1, which highlights its ability to delineate the soft tissue extent of tumor, including extraglandular extension of disease and perineural spread.
Key Considerations
- MRI overcomes many of the limitations encountered by US by providing extended cross-sectional anatomic view of the area of interest and allowing for the detection of perineural tumor spread, deep-tissue extension, and marrow involvement 1.
- The addition of advanced MRI techniques including diffusion-weighted imaging and perfusion imaging, such as dynamic contrast-enhanced, may improve the ability of MRI to distinguish benign from malignant salivary gland tumor 1.
- Fine needle aspiration (FNA) biopsy should be performed to determine the cellular composition and rule out malignancy, as some lesions may represent malignancies like mucoepidermoid carcinoma or adenoid cystic carcinoma.
Recommendations
- Obtain imaging studies, specifically an MRI with contrast, to better characterize the lesion.
- Perform fine needle aspiration (FNA) biopsy to determine the cellular composition and rule out malignancy.
- Refer the patient to an otolaryngologist (ENT specialist) or oral and maxillofacial surgeon for further evaluation and treatment.
- Maintain good oral hygiene and report any changes in size, pain, or new symptoms while waiting for specialist evaluation.
- Treatment depends on the specific diagnosis but often involves surgical excision of the lesion and possibly the affected portion of the gland.
From the Research
Education Class Cystic/Necrotic Lesions
- Cystic lesions of the mandible and maxilla can be recognized with various imaging modalities, including conventional X-ray films, computed tomography, and magnetic resonance imaging 2.
- These lesions can be classified into odontogenic and nonodontogenic cysts, and their diagnosis can be reached by analyzing parameters such as location, relationship to adjacent structures, shape, and others 2, 3.
- Common benign cystic lesions include periapical (radicular) cysts, follicular (dentigerous) cysts, and odontogenic keratocysts, while malignant tumors that often involve the mandible include squamous cell carcinomas, osteosarcomas, and metastatic tumors 3.
- Imaging findings may not always lead to a specific diagnosis, but they can narrow the differential diagnosis and guide further work-up, including biopsy 3, 4.
- MR imaging can be used to distinguish odontogenic keratocysts and ameloblastomas from other cysts, based on parameters such as locularity, solid or cystic pattern, thickness and contrast enhancement of the walls, and homogeneity and signal intensities of the fluids 5.
- Cysts of the jaws can be classified into two categories: odontogenic and nonodontogenic, and key features to differentiate among these cysts have been discussed, including radiographic techniques used to diagnose these lesions 6.
Classification of Cystic Lesions
- Odontogenic cysts:
- Periapical (radicular) cysts
- Follicular (dentigerous) cysts
- Odontogenic keratocysts
- Nonodontogenic cysts:
- Primordial cysts
- Radicular cysts
- Cysts of other types
- Benign tumors:
- Ameloblastomas
- Odontomas
- Ossifying fibromas
- Periapical cemental dysplasia
- Malignant tumors:
- Squamous cell carcinomas
- Osteosarcomas
- Metastatic tumors
Imaging Modalities
- Conventional X-ray films
- Computed tomography (CT)
- Magnetic resonance imaging (MRI)
- Fine-needle aspiration biopsy
- Contrast-enhanced MR studies