Fenestrated internal jugular vein: a rare finding in neck dissection.

Fenestration of the internal jugular vein (IJV) is an extremely rare phenomenon. An 85-year-old woman was referred to our department with T2N0M0 squamous cell carcinoma of the right floor of the mouth. The patient underwent local resection, an ipsilateral modified type 3 radical neck dissection, and microsurgical reconstruction. During neck dissection, a fenestration was observed in the middle of the IJV. No structure passed through the fenestration. Such anatomical variations are rare, but clinicians and surgeons should be aware of them in order to avoid damage to the important vascular structures, especially if a neck dissection is performed.