Retrograde flow in the dural sinuses frequently occurs on the left side in middle-aged and elderly patients during 3D-TOF MR angiography performed with the patient in the supine position. This phenomenon should not be misdiagnosed as a dural arteriovenous fistula.

We report a case of squamous cell carcinoma presumably arising from the left Stensen's duct. The tumor was discovered during management of recurrent left parotitis. Ultrasonography, computed tomography, and magnetic resonance imaging were useful for estimating the tumor and coexisting obstructive parotitis. Relapsing symptoms and the presence of parotitis seemed to be characteristic of tumors of Stensen's duct. For a mass accompanied by obstructive parotitis or relapsing parotitis without salivary calculus, a tumor of Stensen's duct should be included in the differential diagnosis.