Newborn with a skin defect and a bump on the skull

MRI of aplasia cutis
Axial T1 MRI without contrast (above left) and axial T2 (above right) of the brain show an oval lesion in the subcutaneous tissue which is isointense on T1WI and hyperintense on T2WI. Coronal T1 MRI without contrast (below) show a bone defect in the skull beneath the cystic lesion.

The diagnosis was aplasia cutis.