Two case reports of synchronous unilateral pleomorphic adenoma and cystadenolymphoma of the parotid gland with literature review

Background: Synchronous unilateral tumors in the parotid glands account for less than 5–10% of all salivary gland neoplasms. Mostly these are cystadenolymphomas, but tumors of different histological types can be found as well. In these cases it is often pleomorphic adenoma in combination with cystadenolymphoma. Ultrasound is the first choice imaging modality. Case report: We present two patients with two simultaneous tumors in a unilateral parotid gland. In each case, B-mode ultrasound showed two hypoechoic masses, one of which was predominantly cystic. The subsequent use of Virtual Touch Imaging Quantification (VTIQ) showed tumors of elastic tissue. After a parotidectomy, both cases were diagnosed with pleomorphic adenoma combined with cystadenolymphoma. Conclusion: The combination of B-mode ultrasound and VTIQ is an important diagnostic modality and may improve diagnostic accuracy to differentiate between benign and malignant lesions. Every clinician should be aware of the co-existence of different histological types of tumors in unilateral salivary glands.