CT features of parotid gland oncocytomas: a study of 10 cases and literature review

Abstract

Oncocytomas of the salivary glands are rare benign epithelial tumors which occur most commonly in the parotid gland. The aim of our study was to characterize the clinical-radiologic-pathologic spectrum of parotid oncocytomas in a series of 10 cases seen in our institution between January 2003 and November 2008. The CT features of parotid oncocytomas in the largest imaging series of this rare but important benign lesion include a well-defined enhancing tumor with a "deformable" appearance when large, and a non-enhancing curvilinear cleft or cystic component. These CT findings are potentially helpful in distinguishing these benign lesions from other parotid tumors in clinical scenarios that preclude surgical resection or when biopsy results are non-diagnostic. Further studies are advocated to validate the specificity and positive predictive value of these imaging features.

Fig 1.

A 60-year-old man with bilateral parotid oncocytomas. CT scan shows bilateral multifocal and homogeneously enhancing parotid tumors with well-defined margins involving both the superficial (white asterisks) and deep (black asterisks) lobes of the parotid gland.

Fig 2.

A 49-year-old woman with a unilateral solitary parotid oncocytoma. A well-defined tumor with a lobulated contour and homogeneous enhancement is identified on the CT scan in the superficial lobe of the left parotid gland (white asterisk).

Fig 3.

A left parotid oncocytoma in a 68-year-old woman. CT scan reveals a large deformable tumor (white asterisk), which extends medially into the parapharyngeal space through the stylomandibular gap. The contour of the tumor is distorted by the styloid process (black arrow) and the left medial pterygoid muscle (black arrowheads).

Fig 4.

A, A 70-year-old woman with a large right parotid oncocytoma. The large tumor (white asterisk) extends medially through the stylomandibular gap into the parapharyngeal space and demonstrates a nonenhancing curvilinear cleft (black arrow). B, Synchronous bilateral parotid oncocytomas in another 70-year-old woman. CT demonstrates tumors in the right parotid gland (white asterisks), which show homogeneous enhancement, and a large left parotid tumor (black asterisk) with a nonenhancing curvilinear cleft (black arrow).

Fig 5.

A 49-year-old man with a unilateral solitary parotid oncocytoma. The parotid tumor in the superficial lobe of the left parotid gland (white asterisk) has a lobulated contour and shows a cystic component (black arrow).