Image interpretation for squamous cell carcinoma of Stensen duct.

A case of squamous cell carcinoma presumed to have arisen from the right Stensen duct is reported. The patient, a 62-year-old man, was referred to our hospital with swelling in the right cheek. Magnetic resonance imaging (MRI), including contrast-enhanced MRI, and contrast-enhanced computerized tomography (CECT) enabled diagnosis of a solitary mass in the Stensen duct. Fat-suppressed T(2)-weighted imaging, in particular, demonstrated a mass-like lesion in the dilated Stensen duct and obstructive parotitis where the duct transitions into the parotid gland. Gadolinium-DTPA-enhanced T(1)-weighted imaging demonstrated the mass-like lesion surrounded by signal-hyperintense layer showing continuous transition from the thickened Stensen duct wall, which was also hyperintense. The CECT revealed peripheral annular enhancement surrounding the tumorous mass, with no enhancement of the duct wall itself, reflecting an increase in micro blood vessels in the stroma of the neoplasm. These image findings correlated well with subsequent histopathologic findings. A mass with rim enhancement and dilated Stensen duct accompanied by parotitis and no salivary calculus may suggest a differential diagnosis of malignant tumor of Stensen duct.