ARRS 2022 Abstracts

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E1907. Imaging of the Masticator Space: A Pictorial Review
Authors
  1. Issa Khoury; Montefiore Medical Center
  2. Jacqueline Bello; Montefiore Medical Center
  3. Keivan Shifteh; Montefiore Medical Center
Background
The masticator space contains the mastication muscles, mandible, mandibular nerve, and inferior alveolar vein and artery. Inflammatory conditions of the space are particularly common and are usually odontogenic in origin. Lymphovascular malformations are also common specially in pediatric population. Benign and malignant tumors may arise from the different contents of the space. Since clinical assessment of lesions in this space may be difficult, CT and MRI are important for the characterization and mapping of the lesions.

Educational Goals / Teaching Points
The goals of this exhibit are to identify the major anatomic landmarks and contents within the masticator space (MS) as well as surrounding anatomical spaces (buccal, parapharyngeal, parotid); and identify CT and MRI findings of the common and uncommon disease processes of the masticator space and differential diagnosis.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Introductory anatomy of the MS will be discussed, including identifying major anatomical landmarks and contents (muscles of mastication, nerves, bones) and surrounding anatomical spaces (buccal, parapharyngeal, parotid). A case-based approach will be provided to identify and differentiate major disease processes of the MS based on the following classification. Benign findings include vascular/congenital (hematoma, AVM, hemangioma, lyphmangioma); infection (odontogenic abscess, osteomyelitis, chronic infection); acquired (accessory parotid gland, masseteric hypertrophy, V3 denervation, ALS); mandibular lesions (odontogenic keratocyst, dentigerous cyst, ameloblastoma, ABC, central ossifying fibroma); and neoplasms (leiomyoma, neural sheath tumor, JNA). Malignant findings include sarcoma, lymphoma, rhabdomyosarcoma, and metastasis.

Conclusion
Masses of the MS are difficult to evaluate clinically, and CT and MRI are essential for the diagnosis and characterization of these lesions. Malignant tumors may or may not demonstrate bone erosion or violation of the fascia. Infections of the MS may cross the fascia and mimic neoplasms on imaging studies. Perineural spread may occur in tumors involving the MS and its recognition on imaging studies is essential to plan the appropriate treatment.