Performance of Routine MRI Reporting for Parapharyngeal Space Tumors: A Retrospective Radiologic-Pathologic...

Background/Objectives: The parapharyngeal space is a complex anatomical region that houses critical neurovascular structures and serves as the origin of rare tumors, which account for 0.5-1% of head and neck neoplasms. Magnetic resonance imaging (MRI) is useful for their preoperative assessment. However, its accuracy in real-world clinical settings remains underexplored. This study aimed to investigate the diagnostic accuracy of MRI for parapharyngeal tumors at two tertiary centers. Methods: This retrospective study included patients who underwent MRI and surgical excision at two tertiary centers in Saudi Arabia between 2018 and 2024. Two reviewers independently extracted their MRI data and compared them with the final pathological data to determine the diagnostic performance of MRI. Results: Of the 31 patients (58.1% female; median age, 37.5 years), 90.3% had benign tumors. Neurogenic (41.9%) and salivary (25.8%) tumors were most common; 61.3% were located within the pre-styloid space. The benign and malignant groups had comparable baseline characteristics. MRI demonstrated moderate overall diagnostic agreement (κ = 0.525) and near-perfect concordance for schwannomas (κ = 0.912) and paragangliomas (κ = 0.839) but poor agreement for hemangiopericytomas (κ = -0.051). It had high accuracy (90.3%), specificity (92.9%), and negative predictive value (96.3%) for detecting malignancy but limited sensitivity (66.7%) or positive predictive value (50.0%). Nonetheless, cautious interpretation is required due to the limited prevalence of malignancy in the cohort (n = 3). Conclusions: MRI demonstrated high specificity for benign parapharyngeal space lesions in routine clinical reporting within this retrospective cohort, reflecting strong radiologic-pathologic agreement. Estimates of sensitivity and positive predictive value for malignancy were influenced by the limited number of malignant cases. Accordingly, the reported diagnostic performance measures should be interpreted as descriptive and exploratory, characterizing real-world MRI performance rather than definitive diagnostic accuracy.