Post-styloid parapharyngeal neurogenic tumors: imaging-based prediction of nerve origin and clinical outcomes - a single-center retrospective case series.

Introduction: Post-styloid parapharyngeal space (PPS) tumors are rare and predominantly neurogenic. Because tumors arising from the vagus nerve or the cervical sympathetic chain are associated with distinct postoperative morbidities, accurate preoperative identification of the nerve of origin is clinically important for surgical planning and risk counseling. The primary endpoint was the accuracy of imaging-based nerve-of-origin prediction using vessel displacement patterns, compared with intraoperative confirmation. Methods: We retrospectively reviewed adult patients with post-styloid PPS tumors treated at a single center between 1998 and 2023. Vessel displacement patterns on computed tomography (CT) or magnetic resonance imaging (MRI) were used to estimate nerve of origin and were verified intraoperatively in surgically treated patients. Management strategy, pathology (when available), complications, and follow-up outcomes were recorded. Results: Fifteen patients (mean age 44.5 years; 67% male) were identified. A painless neck mass was the most common presenting symptom (53%). Imaging suggested a vagal origin in 11 tumors and a sympathetic chain origin in 4 tumors. Among the 9 surgically treated patients with intraoperative confirmation, imaging correctly predicted the nerve of origin in 8 cases (88.9%). One tumor predicted as vagal in origin was intraoperatively identified as arising from the sympathetic chain and was complicated by postoperative Horner's syndrome. Surgical resection was performed in 9 patients, stereotactic radiosurgery in 2, and active surveillance in 4. Postoperative vocal fold palsy and Horner's syndrome each occurred in one patient. No recurrence or progression was documented during available follow-up. Discussion: Routine cross-sectional imaging of vessel displacement patterns may provide a valuable preoperative estimate of nerve origin for post-styloid PPS neurogenic tumors. This approach may help surgeons individualize treatment strategies and risk assessment. Future multicenter studies with larger surgically verified cohorts are needed to confirm these results.