A 14-year-old child consulted for a right laterocervical swelling evolving for 3 months discovered fortuitously by his mother. This mass was painless, increased in size during the Valsalva maneuver and disappeared completely in the supine position (Figure A). The cervical ultrasound showed dilatation of the right internal jugular vein without a sinuous course. The CT angiography confirmed the diagnosis of a right jugular vein aneurysm with a diameter of 21 mm (Figure B). The conduct was to monitor the patient and to intervene only in case of a complication or a rapid increase in size.