Sclerotic Skull Lesion, Solitary



Sclerotic Skull Lesion, Solitary


Miral D. Jhaveri, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Metastasis


  • Osteoma


  • Fibrous Dysplasia


  • Meningioma-Associated Hyperostosis


  • Paget Disease


Less Common



  • Osteomyelitis, Skull (Chronic)


  • Calcified Cephalohematoma


Rare but Important



  • Calvarium Fracture (Chronic, Depressed)


  • Meningioma (Intraosseous)


  • Hemangioma


  • Craniostenosis


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Outer/inner table: Osteoma


  • Diploic space (DS) ± outer/inner table: Sclerotic metastasis


  • DS expansion + outer > inner table: FD


  • DS expansion + inner > outer table: Paget disease


Helpful Clues for Common Diagnoses



  • Metastasis



    • Most common tumors with intrinsically sclerotic metastases



      • Prostate


      • Breast


      • Lymphoma


    • Any lytic metastasis can become sclerotic after treatment


    • Use contrast-enhanced MR to assess intracranial involvement


  • Osteoma



    • Well-circumscribed, dense, hyperostotic


    • Location



      • Paranasal sinuses (frontal most common)


      • Calvarium


      • Facial bones, mandible


    • Outer table > inner table


  • Fibrous Dysplasia



    • 70% of all FD cases are monostotic


    • Expansile, widened diploic space


    • Imaging patterns relate to relative content of fibrous vs. osseous tissue



      • Classic: “Ground-glass” appearance


      • Sclerotic, cystic, or mixed bone changes also seen


      • Can show variable enhancement, sometimes striking


  • Meningioma-Associated Hyperostosis



    • More common with en plaque meningioma than globular form


    • En plaque meningioma



      • Adjacent bony hyperostosis often disproportionately greater than underlying tumor


    • Cause of hyperostosis is controversial



      • Reactive or tumoral infiltration


  • Paget Disease



    • Older patient (vs. younger with fibrous dysplasia)


    • Late sclerotic phase



      • Widening of diploic space + coarsened trabeculae


      • Inner table, diploic space more involved than outer table


      • Round or oval area of sclerosis (usually within prior areas of “osteoporosis circumscripta”)


      • Diffuse > > solitary involvement


Helpful Clues for Less Common Diagnoses



  • Osteomyelitis, Skull (Chronic)



    • Rare in calvarium



      • Classic imaging finding = “button sequestrum”


      • Dense island of dead bone within well-defined lytic area


      • Also seen in numerous other entities


      • Common: Eosinophilic granuloma, healing burr hole


      • Less common/rare: Tuberculous osteitis, radiation-induced bone necrosis, metastasis, Paget disease


    • More common in skull base



      • Spread of infection from paranasal sinuses, mastoid, petrous apex air cells


      • Ill-defined area of mixed osteosclerosis, lysis


    • ± Epidural/subdural empyema, brain abscess


    • Consider contrast-enhanced MR to assess extent


  • Calcified Cephalohematoma



    • Usually associated with birth trauma



      • Acute subperiosteal hemorrhage



      • Healing stage may result in rim calcification


    • Late sequelae



      • Calcified rim incorporated into outer table


      • Outer table eventually becomes sclerotic, thickened


Helpful Clues for Rare Diagnoses

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

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