<prompt> Most common primary malignant tumour of parotid glandWahin tumourMucoepidermoid CancerAcinic cell CancerAdenoidcystic carcinoma  <response>: - Most common primary malignant tumor of parotid gland is Mucoepidermoid carcinoma - Mucoepidermoid carcinoma Malignant neoplasm of variable biological aggressiveness Composed of a mixture of squamous, mucous secreting intermediate cells. 