Adenoid Cystic Carcinoma (ACC) Infiltrating the Skull Base: A Systematic Review of Clinical Characteristics and Management Strategies.

[BACKGROUND/AIM] To systematically review the patient characteristics and management approaches of adenoid cystic carcinoma (ACC) infiltrating the skull base.

[MATERIALS AND METHODS] According to PRISMA guidelines, PubMed, Scopus, and Cochrane were searched to retrieve studies reporting management protocols and survival outcomes of patients with skull base ACCs. Patient characteristics, management strategies, and outcomes were investigated.

[RESULTS] The review encompassed 17 studies involving 171 patients, with a female predominance (57.9%) and a mean age of 49±7.12 years. ACCs mostly infiltrated the paranasal sinus (22.2%), cavernous sinus (8.8%), and nasopharynx (7.1%). Perineural invasion was reported in 6.4% of cases. Facial pain, nasal obstruction, and facial paresthesia were the most common symptoms. Surgical resection (45.6%) was favored over biopsy (12.2%). Employing the free flap technique (4.7%), surgical reconstruction of the bony defect after resection was performed using abdominal and anterior thigh muscle grafts in 1.8% of patients each. As adjuvant management, 22.8% of cases had radiotherapy and 14.6% received chemotherapy. Recurrence of skull base ACCs occurred in 26.9% of cases during a mean follow up-time of 30.8±1.8 months.

[CONCLUSION] Skull base ACCs pose a surgical challenge mainly due to their proximity to critical neurovascular structures and aggressive behavior. Surgical resection and radiotherapy are shown to be safe and effective treatment modalities. The dismal prognosis and limited data on non-surgical strategies highlight the need for further evaluation of the current management paradigm and upraising innovative therapies to improve patient mortality and quality of life.