Macrocephaly can be the presenting clinical finding in a range of neurologic conditions that range from benign enlargement of subarachnoid spaces to tumors and metabolic disorders resulting from abnormal prenatal or postnatal increases in the volume of one of the intracranial compartments while the cranial sutures are open.

Macrocephaly affects up to 5% of the pediatric population and is defined as an abnormally large head with an occipitofrontal circumference (OFC) >2 standard deviations (SD) above the mean for a given age and sex.

There is a wide range of causes of macrocephaly, from benign to malignant, for which imaging plays a key role in the diagnosis and clinical guidance. Our aim is to review the distinct and prevalent neuroimaging findings in the evaluation of the macrocephalic infant.

There is a wide range of causes of macrocephaly, from benign to malignant, for which imaging plays a key role in the diagnosis and clinical guidance. Our aim is to review the distinct and prevalent neuroimaging findings in the evaluation of the macrocephalic infant.

In this review, we seek to underline the clinical aspects of macrocephaly and megalencephaly, emphasizing the main differential diagnosis with a major focus on common genetic disorders.