Hyperostosis frontalis interna is an unexplained irregular thickening of the inner table of the frontal bone. Hyperostosis frontalis interna was first identified in 1719 by Morgagni as a symptom of a more generalized syndrome characterized by virilism and obesity. Most current studies have shown hyperostosis frontalis interna to be a sex- and age-dependent phenomenon, and females manifest a significantly higher prevalence of hyperostosis frontalis interna than males. In this article, the authors report the clinical case of hyperostosis frontalis interna in a 7-year-old child who had severe traumatic brain injury in the past; review the related literature; and discuss the clinical, radiological, and therapeutic features of this condition.