A 57-year-old patient complains of a tumor in the left parotid region, which appeared 3 years ago. Over the past six months, the tumor has increased significantly. Objectively: there is a non-mobile lobulated tumour in the left parotid region, palpation causes minor pain reaction. The skin over the tumour plicates easily, its upper part has well-defined margins, the bottom part grows into the depth of gland. The tumour is 3x2,5 cm large. What is your provisional diagnosis?