hair on end sign

Young adult

with a thick skull. Lateral radiograph of the skull shows widening of the diploic space, thinning of the inner and outer tables of the skull, and an overall hair-on-end appearance with sparing of the occipital bone.The diagnosis was thalassemia.

Imaging of

skull vault tumors in adults. Miscellany. Paget disease (a, b) CT (a) and X-ray (b): Characteristic mixed bone lysis and sclerosis, cortical bone thickening, and expansion. Osteoporosis circumscripta cranii CT (c, d): large geographic radiolucent areas involving medullar and cortical bone in frontal and occipital regions (arrows). Amyloidoma (e, f) CT (e) and T2WI (f): Giant heterogeneous mass with marked T2 hypointensity and calcifications. Renal osteodystrophy CT (g): shows characteristic “salt-and-pepper pattern.” Brown tumor (h, i): unspecific well-defined, cystic appearance (arrows). Thalassemia CT (j): Diffuse diploic widening and “hair-on-end” appearance (arrow) with characteristic occipital bone preservation (arrowhead). Bone sarcoidosis (k, l) CT (k) and T2WI (l): Mixed predominantly lytic multiple lesions with lace-like internal pattern of calcification and T2 hypointensity (dashed arrows). Osteitis CT (m, n): Bone focal lysis and erosions of osteitis (arrows) contiguous to a frontal sinusitis complicated with intracranial laminar abscess (dashed arrow)