Correct diagnosis of Warthin tumor in the parotid gland with dynamic MRI.

Warthin tumor (WT) is a benign tumor of the salivary gland primarily affecting middle-aged men. WT is almost exclusively located in the parotid gland and tend to grow slowly without symptoms. Although fine needle aspiration cytology (FNAC) often correctly diagnoses these tumors, they are occasionally misdiagnosed as malignant. Our study sought to distinguish between WT and non-WT using dynamic MRI. In dynamic MRI, a series of images are taken over time measuring the intensity of gadolinium uptake by the parotid. We examined two patients for this study. The first was a 53-year old male, heavy smoker, experiencing manic-depressive episodes. He received a brain MRI at which time his parotid tumor was discovered. Parotid FNAC indicated a squamous cell carcinoma. The second patient was a 76-year old male, moderate smoker and drinker, who had been complaining about swelling in the neck. FNAC of the parotid indicated acinic cell carcinoma and gadolinium-enhanced MRI suggested the tumor was malignant. Prior to surgically extracting of these masses, we performed dynamic MRI on each patient. Both tumors exhibited a pattern consisting of rapid enhancement and rapid attenuation, the pattern of which is characteristic of WT. The surgical specimens confirmed that both were WTs without malignant transformation. Our findings indicate that dynamic MRI is a useful tool for preoperative diagnosis of WT, where other examinations indicate malignancy. Early and correct diagnosis of WT can minimize the use of invasive procedures, and eliminate the stress placed on the patient from a diagnosis of cancer.