Abstract
Any posterior midline cystic or soft tissue scalp mass in an infant needs evaluation with MRI brain and MRV brain to look for intracranial extension of the lesion. One of the differential considerations is an atretic cephalocele, which can be a difficult diagnosis, especially when the cystic lesions are small. The presence of a small calvarial defect adjacent to the cystic mass and a persistent primitive falcine vein, which points towards the cystic mass, are imaging clues to this diagnosis. Correct diagnosis is needed prior to surgical resection to avoid potentially serious postoperative complications.