The clinical manifestations of hyperostosis frontalis interna: A qualitative systematic review of cases

Hyperostosis frontalis interna (HFI) is a condition defined as abnormal bone growth on the posterior aspect of the frontal bone. Despite uncertainties regarding its etiology and prognosis, clinicians typically consider HFI a benign pathology. There are no studies organizing all the possible manifestations of the disease. The present study aims to organize all the clinical manifestations of HFI within the current case report/series literature. A blinded PRISMA-guided search of HFI case reports and case series yielded 43 relevant articles and provided 110 patients for analysis. The symptoms presenting alongside HFI were extracted and tabulated. We found high-frequency clinical manifestations of HFI (>20% of patients) to include headaches, obesity, vertigo/dizziness symptoms, cognitive decline, and depression. An additional 15 symptoms were tabulated at frequencies found to be less than 20%. Based on our analysis, we suggest the constellation of high-frequency symptoms can offer a more comprehensive clinical picture of symptomatic HFI which may be valuable to consider for clinicians and future researchers in the field of HFI.