Female patient, 40 years old presented with Rt. Parotid swelling. a Axial T1-weighted MRI showed large low SI infiltrating mass involving both superficial and deep lobes of the Rt. Parotid gland encasing the carotid sheath vessels. The mass extended to the Rt. parapharyngeal space and RT side of the oropharynx, RT masticator space and retromolar region. b Coronal T2 showed that the mass has heterogeneous high SI. c Axial post contrast T1 with fat suppression MRI: the lesion showed diffuse heterogeneous enhancement. d DWI showing the lesion was hyperintense. e ADC map with mean ADC value = 2 × 10−3 mm2/s. f TIC showing type C curve (TTP = 90 S, WR < 30%). Pathological diagnosis: acinic cell carcinoma.