AJNR Am J Neuroradiol. 2026 Aug 17:ajnr.A9595. doi: 10.3174/ajnr.A9595. Online ahead of print.
ABSTRACT
BACKGROUND: Extra-articular extension of temporomandibular joint (TMJ) lesions may mimic primary pathology of adjacent compartments, leading to misdiagnosis and inappropriate management.
PURPOSE: Building on our prior work describing intracranial extension of TMJ lesions, we sought to characterize the clinical presentation, imaging features, and pathologic distribution of extra-articular extracranial lesions across five anatomical compartments, and to evaluate the clinical impact of radiologic misclassification.
DATA SOURCES: A search of MEDLINE, SCOPUS, and Embase, in accordance with PRISMA guidelines, yielded 3,228 records.
STUDY SELECTION: After screening, 236 studies comprising 270 cases were included; studies without imaging descriptions or reporting exclusively intracranial extension were excluded.
DATA ANALYSIS: Extra-articular extracranial extension was categorized into five compartments: central skull base, temporal bone, deep neck spaces, facial bones, and paranasal sinuses; ≥2 compartments was classified as multicompartment extension. Descriptive statistics were performed using Excel and STATA.
DATA SYNTHESIS: TMJ lesions most commonly extended to deep neck spaces (n=52), temporal bone (n=44), and central skull base (n=42). Clinical presentation varied by compartment, including otologic symptoms with temporal bone extension and preauricular swelling mimicking parotid pathology in deep neck space involvement. Pigmented villonodular synovitis (PVNS)/tenosynovial giant cell tumor (T-GCT) predominated in temporal bone, deep neck, and multicompartment disease, while synovial chondromatosis was most common in skull base extension. Among cases with reported imaging differentials, imaging misclassification was highest in temporal bone (79%) and facial bone (75%) involvement. Radiologic misdiagnosis led to six cases of unnecessary parotidectomy and five cases of delayed diagnosis or avoidable patient morbidity.
LIMITATIONS: Inherent biases of case report and case series literature, including variability in reporting of imaging features, clinical presentation, management, and follow-up.
CONCLUSIONS: Extra-articular extracranial TMJ lesions demonstrate compartment-specific clinical presentations, imaging patterns and pathological distributions that, when recognized, can guide accurate diagnosis and prevent radiologic misclassification. Misdiagnosis rates across all compartments underscore the importance of systematic TMJ assessment on cross-sectional imaging and inclusion of TMJ pathology on the imaging differential in adjacent head and neck lesions.
PMID:42608195 | DOI:10.3174/ajnr.A9595
