2026 Poster Presentations
P083: COLLISION SKULL BASE TUMORS: CHONDROSARCOMA AND JUVENILE NASOPHARYNGEAL ANGIOFIBROMA. CASE REPORT AND REVIEW OF LITERATURE.
Alaa S Montaser, MD; Rabih G Tawk, MD; Joseph T Breen, MD; Angela M Donaldson, MD; Krishnan Ravindran, MD; Richard W Byrne, MD; Mayo Clinic - Florida
Background: Skull base chondrosarcomas represent a rare malignant pathological entity which accounts for 0.15% of intracranial tumors. Juvenile nasopharyngeal angiofibromas (JNA) are rare, benign but locally aggressive, highly vascular tumors comprising up to 0.5% of all head and neck tumors. Although collision skull base tumors represent a paucity, the co-existance of skull base chondrosarcoma and JNA has never been reported in the literature to date.
Case discription: a 17-year-old male presented with nasal obstruction for a few months; imaging work-up demonstrated a mass in the right nasal cavity extending into right nasopharyngeal space, most consistent with JNA. Additionally, initial imaging showed a localized area of abnormal signal intensity affecting the right petrous apex, however, it was completely distinct from the JNA and was thought to represent a benign process. The patient underwent embolization of the JNA followed by endoscopic endonasal resection. Postoperative follow-up imaging demonstrated no evidence of residual or recurrent disease; no changes were noted to the right petrous apex lesion. Patient was lost to follow-up, then presented 9 years later with persistant right-sided hearing loss that prompted work-up; head CT and brain MRI demonstrated a large heterogenously enhancing expansile mass centered at the petroclival region, extending into middle and posterior fossae, invading the right cavernous sinus and significantly compressing the brainstem and cerebellum. An endoscopic endonasal biopsy of the lesion was performed, after which the patient underwent a staged surgical resection via a retrosigmoid craniotomy followed by endoscopic endonasal resection. Both surgical interventions were uneventful, and he had an excellent postoperative recovery. Histopathological examination was consistent with chondrosarcoma WHO grade II. Following a multidisciplinary discussion, patient proceeded with adjuvent proton beam radiation therapy.
Conclusion: collision skull base tumors represent an exceedingly rare occurance yet have a great impact on patients’ outcomes and overall quality of life. Our report highlights the importance of considering collision tumors in the differential diagnosis of skull base lesions, which may provide guidance for follow-up intervals and optimal surgical strategies. To date, this is the first report in the literature of concomitant skull base chondrosrcoma and juvenile nasopharyngeal angiofibroma.
