Role of stereotactic radiosurgery for recurrent skull base acinic cell carcinoma: illustrative case.

Background: Acinic cell carcinomas (AcCCs), rare malignancies of the salivary glands, often recur and metastasize, particularly in the skull base. Conventional radical resection can be invasive for skull base AcCCs adjacent to cranial nerves and major vasculature, and the effectiveness of stereotactic radiosurgery (SRS) as an alternative is not well established.
Observations: This case report details the application of SRS for recurrent skull base AcCCs. A 71-year-old male with a history of resection for a right mandibular AcCC 23 years earlier experienced tumor recurrence involving the right cavernous sinus and nasal cavity. He underwent endoscopic transnasal surgery followed by SRS targeting different tumor locations-the cavernous sinus to the pterygopalatine fossa, maxillary sinus, and clivus-each with a prescribed dose of 20 Gy to the 40% to 50% isodose line. After the first skull base metastasis, additional sessions of localized SRS after endoscopic surgery led to a 12-year survival without sequela.
Lessons: This is a report indicating that SRS for skull base AcCCs can achieve favorable local control, functional preservation, and long-term survival. SRS may be suitable for skull base AcCC given the lesion's tendency toward multiple local recurrences. Further investigation is needed to validate the treatment's efficacy.