Extraordinary cerebral venous drainage pathway with mastoid emissary and posterior external jugular veins detected by contrast-enhanced neck computed tomography.

An extraordinary cerebral venous drainage pathway and dilated vein at the left posterior cervical region were detected with routine contrast-enhanced neck computed tomography exam. The left sigmoid sinus was drained by dilated mastoid emissary vein (MEV). The MEV continued as posterior auricular and posterior external jugular veins (PEJVs). The left PEJV directly drained into subclavian vein. Atretic right transverse sinus, left facial vein forming the external jugular vein, atresia and hypoplasia of upper internal jugular veins at the right and left sides, respectively, were the other uncommon findings in our case. Detecting venous variations may prevent complications during surgical and interventional procedures, so the radiologists should examine the superficial cervical veins closely.