Lytic Skull Lesion, Solitary



Lytic Skull Lesion, Solitary


Miral D. Jhaveri, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Skull Normal Variants


  • Surgical Defects, Calvarial



    • Burr Holes


    • CSF Shunts and Complications


  • Metastasis


Less Common



  • Epidermoid Cyst


  • Langerhans Cell Histiocytosis


  • Plasmacytoma


  • Paget Disease


  • Hemangioma


  • Dermoid Cyst


  • Fibrous Dysplasia


  • Leptomeningeal Cyst


  • Osteomyelitis


Rare but Important



  • Cephalocele


  • Tuberculosis


  • Neurosarcoidosis


  • Sinus Pericranii


  • Aneurysmal Bone Cyst


  • Aggressive Fibromatosis


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Margins of lytic lesion helpful



    • Surgical defects: Well-marginated


    • Metastasis, osteomyelitis: Permeative


    • Epidermoid: Dense sclerotic


    • Histiocytosis: “Beveled” edge


Helpful Clues for Common Diagnoses



  • Skull Normal Variants



    • Vascular grooves



      • Inner table: Meningeal arteries, veins


      • Outer table: Superficial temporal artery


    • Venous channels



      • Thin-walled veins, venous “lakes”


      • Connect meningeal veins/dural venous sinuses with pericranial veins


      • Diploic venous channel can usually be traced into venous lakes


    • Pacchionian (arachnoid) granulations



      • Within/adjacent to dural venous sinus


      • Round/oval filling defect in venous sinus


      • Large lesions remodel inner table


      • CSF density/signal intensity


  • Surgical Defects, Calvarial



    • Check history!


    • Burr holes, surgical defects well-marginated


  • Metastasis



    • Destructive, permeative


    • Enhancing mass centered in diploe


    • ± Associated dural/scalp soft tissue


    • Often known primary malignancy



      • Breast, lung, prostate most common


Helpful Clues for Less Common Diagnoses



  • Epidermoid Cyst



    • Involves both inner, outer tables


    • Well-defined


    • Lacks central trabeculae


    • Dense sclerotic margins


    • Typically round or lobulated


    • Restricts (hyperintense) on DWI


  • Langerhans Cell Histiocytosis



    • “Eosinophilic granuloma”


    • Well-defined lytic lesion


    • “Beveled” edge (inner table involved > outer)


    • No marginal sclerosis


    • ± Adjacent soft tissue mass


    • < 5 years


    • “Hole within hole”, “button sequestrum” on NECT


  • Plasmacytoma



    • Lytic lesion with scalloped, poorly marginated, non-sclerotic margins


    • Often large at presentation


    • Biconvex expansion of involved bone


  • Paget Disease



    • Lytic phase: Well-defined lucent defect


    • “Osteoporosis circumscripta”


    • Frontal > occipital


    • Inner & outer tables both involved; inner usually more


    • Cortical thickening, coarse trabeculation → hypointense T1/T2WI


  • Hemangioma



    • Lytic diploic space lesion


    • Well-circumscribed


    • “Spoke wheel” or “reticulated” pattern


    • Strong enhancement


  • Dermoid Cyst



    • Well-circumscribed unilocular cyst containing fat


    • Expands diploe



    • Commonly near the anterior fontanelle, glabella, nasion, vertex, subocciput


  • Leptomeningeal Cyst



    • “Growing fracture” on radiography/NECT


    • Late complication of skull fracture with dural laceration


    • Smoothly marginated skull defect


    • Hyperintense on T2WI


  • Osteomyelitis



    • Usually complication of trauma, sinusitis, mastoiditis


    • Frontal > temporal bone


    • Mixed lytic/proliferative lesion


    • Moth-eaten/permeative medullary & cortical destruction


    • “Pott puffy tumor” = frontal soft tissue swelling


    • Often associated: Epidural abscess!


Helpful Clues for Rare Diagnoses

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Aug 7, 2016 | Posted by in NEUROLOGY | Comments Off on Lytic Skull Lesion, Solitary

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