[en] Preoperative parotid gland tumor diagnosis is important, especially regarding the grade of malignancy. We studied histopathology magnetic resonance imaging MRI findings and apparent diffusion coefficient (ADC) values in 81 patients with parotid gland tumors. Mean ADC in Warthin tumor and cancer was significantly lower than in pleomorphic adenoma. Three of 4 cases with high-grade malignancy had lower ADC (<1.0), whereas 17 of 18 with pleomorphic adenoma had higher of ADC (>1.0). We found ADC to be useful in distinguishing pleomorphic adenoma from high-grade malignancy. (author)