International Journal of Clinical & Medical Images

Clinical Image

Hyperostosis Frontalis Interna (HFI) is a benign continuous overgrowth of the inner table of the frontal bone, respecting the periosteum and cortical bone. Old post-menopausal women are most affected and its physiopathology remains unclear, although, some authors report a hormonal imbalance influence. It is mostly discovered incidentally through imaging; however, some patients may suffer from headaches due to frontal lobe compression. When associated with obesity, virilism, and mental disorders it forms the Morgagni-Stewart-Morel syndrome. Imaging is the examination of choice to its diagnosis, through X-Ray, CT scan or MRI. It shows a lobulated thickening of the inner table of the frontal bone, that is bilateral and symmetrical, well limited, without crossing the sagittal sinus area medially. Hershkovitz and al. have classified four types of HFI, depending on its severity, from A to D: Type A: Elevation of endocranial frontal bone under 10mm, unilateral or bilateral, usually on the anteromedial part of the frontal bone. Type B: Nodular overgrowths of the endocranial frontal bone <25% of the frontal bone. Type C: Extensive nodular overgrowth with irregular thickening up to 50% of the endocranial frontal bone surface. Type D: Extensive overgrowth of over 50% of the endocranial frontal bone. In Figure 1, we show the case of a 70-year-old male patient, consulting for chronic headaches, to which a head CT scan revealed a type D hyperostosis frontalis interna