<prompt> Which of the following malignant salivary gland tumours has a tendency for perineural invasion?Mucoepidermoid carcinomaAdenoid cystic carcinomaAdenocarcinomaAcinous cell carcinoma  <response>: Adenoid cystic carcinoma has a propensity to spread by perineural invasion. Depending on site most common nerves involved are maxillary and mandibular division of trigeminal. 