Cerebellar Mass



Cerebellar Mass


Gregory L. Katzman, MD, MBA



DIFFERENTIAL DIAGNOSIS


Common



  • Cerebral Ischemia-Infarction, Acute


  • Hypertensive Intracranial Hemorrhage


  • Neoplasms



    • Medulloblastoma (PNET-MB)


    • Pilocytic Astrocytoma


    • Hemangioblastoma


    • Metastases, Parenchymal


Less Common



  • Enlarged Perivascular Spaces


  • “Tumefactive” Demyelinating Disease



    • Multiple Sclerosis


    • ADEM


  • Abscess


  • Cerebellitis, NOS


  • Vascular Malformation, with/without Hemorrhage



    • Cavernous Malformation


    • Arteriovenous Malformation


    • Dural A-V Fistula


Rare but Important



  • Tuberculosis


  • Glioblastoma Multiforme


  • Dysplastic Cerebellar Gangliocytoma


  • Oligodendroglioma


  • Ganglioglioma


  • Remote Cerebellar Hemorrhage


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Child vs. adult



    • Child: Neoplasm > infection, demyelinating disease


    • Adult: Ischemia, hypertensive hemorrhage > neoplasm


Helpful Clues for Common Diagnoses



  • Cerebral Ischemia-Infarction, Acute



    • PICA distribution most common



      • DWI restriction w/correlating ADC map


      • Early cortical swelling


      • “Hemorrhagic transformation” in 15-45%


  • Hypertensive Intracranial Hemorrhage



    • Round/elliptical high density mass


    • 10% occur in pons, cerebellum


  • Medulloblastoma (PNET-MB)



    • 4th ventricle > cerebellum


    • Desmoplastic variant


  • Pilocytic Astrocytoma



    • Best clue: Cystic mass + enhancing mural nodule


    • Childhood (not adult) tumor


  • Hemangioblastoma



    • Adult with intra-axial posterior fossa mass with cyst, enhancing mural nodule abutting pia


    • May be associated with von Hippel-Lindau syndrome


  • Metastases, Parenchymal



    • Intra-axial posterior fossa mass in middle-aged/older adult? Think metastasis!


    • Can be solitary but look for other lesions


Helpful Clues for Less Common Diagnoses



  • Enlarged Perivascular Spaces



    • Fluid-filled spaces that look like CSF, surround/accompany penetrating arteries


    • No diffusion; may have FLAIR hyperintense parenchymal rim


  • Multiple Sclerosis



    • Fulminant acute plaque or conglomeration of acute plaques forming mass lesion(s)


    • May display ring enhancement simulating tumor or abscess


    • Most common disabling CNS disease of young adults; 1:1000 in developed countries


  • ADEM



    • Lesions 10-14 days following infection/vaccination


    • Large flocculent FLAIR hyperintensity but with less mass effect than that expected


    • Punctate, ring, incomplete ring, peripheral enhancement


  • Abscess



    • Especially in children


    • Ring-enhancing lesion



      • High signal on DWI, low ADC


      • T2 hypointense rim with surrounding edema


    • Central necrotic area may show presence of acetate, lactate, alanine, succinate, pyruvate, amino acids on MRS


  • Cerebellitis, NOS



    • Typically occurs as a primary infectious, post-infectious, post-vaccination, or idiopathic disorder


    • Variable enhancement → none to intense; meningeal enhancement can be seen


    • Abnormal T2 hyperintensity & swelling



    • Bilateral diffuse hemispheric abnormalities are most common (73%)


  • Cavernous Malformation



    • “Popcorn ball” appearance with complete hypointense hemosiderin rim on T2WI MR


    • NECT: 40-60% Ca++


  • Arteriovenous Malformation



    • “Bag of black worms” (flow voids) on MR with minimal/no mass effect


    • Flow-related aneurysm on feeding artery 10-15%; intranidal “aneurysm” > 50%


  • Dural A-V Fistula



    • Best imaging tool: DSA with superselective catheterization of feeders


    • Dural AVF involving the region of the foramen magnum, tentorium, torcula Herophili, or posterior fossa veins (e.g., inferior vermian vein) may affect cerebellum


    • Most often presents with hemorrhage


Helpful Clues for Rare Diagnoses



  • Tuberculosis



    • CECT: “Target sign” → central Ca++ or enhancement surrounded by enhancing rim


    • T1 C+: Solid homogeneous to rim enhancement; ± central necrosis


    • MRS: Prominent lipid, lactate but no amino acid resonances


  • Glioblastoma Multiforme



    • Thick irregular enhancing rind of neoplastic tissue surrounding necrotic core


    • Characterized by necrosis and neovascularity


    • Viable tumor extends far beyond signal abnormalities


  • Dysplastic Cerebellar Gangliocytoma



    • Widened cerebellar folia with a striated appearance on MR


    • Thinning of skull may be apparent


    • a.k.a., Lhermitte-Duclos disease, associated with Cowden syndrome


  • Oligodendroglioma



    • Partially Ca++ subcortical/cortical mass in middle-aged adult


    • Majority calcify → nodular or clumped Ca++ (70-90%)


    • May expand, remodel, erode calvarium


  • Ganglioglioma



    • Partially cystic, enhancing, cortically based mass in child or young adult


    • Ca++ common → 35-50%


    • Cortical dysplasia is commonly associated


  • Remote Cerebellar Hemorrhage



    • Occurs after supratentorial craniotomy


    • Superior cerebellar folia



      • Bilateral (33%)


      • Contralateral to side of surgery (29%)


      • Ipsilateral (22%); isolated vermian (9%)






Image Gallery









Axial T2WI MR demonstrates a typical case of PICA acute infarction as hyperintensity associated with swelling in the right cerebellar hemisphere image and lateral medulla image.






Axial NECT shows a large high density mass in the left cerebellar hemisphere image with some adjacent areas of slightly lesser increased attenuation image, indicating active hemorrhage.







(Left) Axial T1 C+ MR shows a poorly defined mass with components in vermis, right cerebellar hemisphere with irregular pattern of enhancement image. Note temporal horn enlargement from obstructive hydrocephalus image. (Right) Axial T1 C+ MR shows classic cystic cerebellar pilocytic astrocytoma with nonenhancing rim image, robustly enhancing mural nodule image.

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Aug 7, 2016 | Posted by in NEUROLOGY | Comments Off on Cerebellar Mass
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