Prognostic importance of the lymphovascular invasion in head and neck adenoid cystic carcinoma: A systematic review and meta-analysis

•Solid/higher-grade AdCC has an increased chance of presenting vascular invasion.•Vascular invasion in AdCC is associated with lymph node metastasis and death.•Vascular invasion in AdCC is associated with a significantly lower survival rates.•Vascular invasion is a determinant of worse prognosis for head and neck AdCC.