Thin Skull, Localized



Thin Skull, Localized


Miral D. Jhaveri, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Skull Normal Variants



    • Parietal Thinning


    • Squamous Temporal, Occipital Bones


  • Arachnoid Cyst


  • Mega Cisterna Magna


Less Common



  • Slow Growing Neoplasm



    • Oligodendroglioma


    • DNET


    • Ganglioglioma


    • Diffuse Astrocytoma, Low Grade


  • Paget Disease


  • Scalp Lesions



    • Dermoid Cyst


    • Epidermoid Cyst


    • Neurofibroma


Rare but Important



  • Meningioma


  • Linear Scleroderma (Coup de Sabre)


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Evaluate underlying brain, overlying scalp!


Helpful Clues for Common Diagnoses



  • Skull Normal Variants



    • Parietal, squamous thinning


    • Inner table intact; diploe, outer table thin


  • Arachnoid Cyst



    • Well-delineated CSF-like extra-axial mass


    • Pressure erosion of adjacent calvarium


    • 50-65% middle fossa; 5-10% convexity


  • Mega Cisterna Magna



    • Enlarged cisterna magna & intact vermis, normal cerebellar hemispheres


    • Scalloped occipital squamae


Helpful Clues for Less Common Diagnoses



  • Slow Growing Neoplasm



    • Any cortically based slow growing neoplasm can cause inner table scalloping


    • Oligodendroglioma



      • Partially Ca++ cortical/subcortical mass


    • DNET



      • Young patient, chronic epilepsy


      • “Bubbly” cortical mass


    • Ganglioglioma



      • Partially cystic enhancing mass (child/young adult)


    • Diffuse Astrocytoma, Low Grade



      • White matter > cortex, nonenhancing


  • Paget Disease



    • “Osteoporosis/osteolysis circumscripta”


    • Early destructive phase



      • Well-defined lysis; frontal > occipital


      • Both inner, outer tables involved (inner usually more)


  • Scalp Lesions



    • Pressure erosion of outer table


    • Dermoid, epidermoid cysts; neurofibroma

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Aug 3, 2016 | Posted by in NEUROLOGY | Comments Off on Thin Skull, Localized

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