MSFinals-4166

A worried 28-year-old mother expresses concern about a lump that has emerged on her infant’s head, stating with certainty that it was not present at birth and was only noticed half an hour ago. The baby was delivered vaginally with forceps 10 hours ago at 39 weeks gestation.

Upon examination, there is a clearly defined, soft swelling that does not cross suture lines and is located on the parietal bone. The baby appears to be in good health otherwise, with normal skin color and tone, as well as regular vital signs.

What is the most probable diagnosis?