Ring-Enhancing Lesion, Multiple



Ring-Enhancing Lesion, Multiple


Yoshimi Anzai, MD, MPH

Judy Tan, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Metastases Parenchymal


  • Abscess


  • Multiple Sclerosis


  • ADEM


  • Neurocysticercosis


Less Common



  • Tuberculosis


  • Opportunistic Infection, AIDS


  • Lymphoma, Primary CNS


  • Radiation and Chemotherapy


  • Multifocal Glioblastoma Multiforme


  • Subacute Intracerebral Hematomas


  • Subacute Cerebral Infarctions


Rare but Important



  • Fungal Diseases


  • Parasites, Miscellaneous


  • Lyme Disease


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Ring-enhancing lesions are most commonly related to tumor, abscess, & demyelination


  • Smooth, thin ring enhancement is typical of an organizing abscess


  • Thick, irregular rings suggest a necrotic neoplasm


Helpful Clues for Common Diagnoses



  • Metastases Parenchymal



    • Associated with substantial vasogenic edema for relative size of lesion


    • Ring-enhancing lesions at corticomedullary junctions


  • Abscess



    • Thin T2 hypointense rim characteristic


    • DWI shows restriction within abscess


    • Ventriculitis, meningitis may be present


    • Proton MRS of abscess cavity: Presence of cytosolic amino acids (0.9 ppm), succinate (2.4 ppm), & acetate (1.92 ppm)


    • Risk factors: Sepsis, immunocompromised, right to left pulmonary shunt


    • Multifocal disease often caused by septic emboli or paranasal sinus infection


  • Multiple Sclerosis



    • Enhancement indicates acute demyelination


    • Mass effect usually less than expected for size of lesion


    • Coexistence of enhancing & nonenhancing lesions due to relapsing, remitting nature of disease


    • Perivenular location “Dawson fingers” & undersurface of corpus callosum typical


  • ADEM



    • Usually monophasic


    • History of recent viral illness or immunization


    • Multifocal white matter (WM) &/or basal ganglia (BG) lesions


    • May have with punctate, ring, incomplete ring, or peripheral enhancement


    • May mimic multiple sclerosis (MS)


  • Neurocysticercosis



    • Parasitic infection caused by pork tapeworm, Taenia solium


    • Cyst with a scolex is pathognomonic


    • 4 stages: Vesicular, colloidal vesicular, granular nodular, nodular calcified


    • Ring enhancement seen in colloidal vesicular & granular nodular stages


Helpful Clues for Less Common Diagnoses



  • Tuberculosis



    • Associated with TB meningitis in 50%


    • Caseating TB granulomas often have markedly T2 hypointense centers


    • Infants, children, & immunocompromised are predisposed


    • Review CXR to exclude miliary TB or primary TB infection


  • Opportunistic Infection, AIDS



    • Multiple ring-enhancing lesions in HIV+ patient: Consider toxoplasmosis, TB, pyogenic/fungal abscess, & lymphoma


    • Toxoplasmosis is most common opportunistic infection



      • BG & gray-white matter junctions


      • Asymmetric “target sign”: Enhancing eccentric nodules within abscess cavity


    • MRS may differentiate Toxo from lymphoma; NAA & choline usually nearly absent (Toxo)


  • Lymphoma, Primary CNS



    • Subependymal location of lesions


    • Ring enhancement seen in HIV+ patients with lymphoma


    • MRS: Elevated choline peak


    • PET: Hypermetabolic



    • Perfusion MR: Hyperperfusion


  • Radiation and Chemotherapy



    • Radiation necrosis may cause multiple enhancing lesions


    • Often difficult to differentiate from recurrent tumor


    • MRS & MR perfusion may be useful



      • MRS: No elevated choline


      • MR perfusion: Hypoperfusion


  • Multifocal Glioblastoma Multiforme



    • Seen in malignant transformation of low grade glioma & spread of primary GBM


    • Metachronous lesions uncommon


  • Subacute Intracerebral Hematomas



    • History of trauma, coagulopathy, amyloid angiopathy


    • Look for blood products on MR (especially on GRE/T2*/SWI sequence)


  • Subacute Cerebral Infarctions



    • Exclude vasculitis & embolic phenomenon as cause for multiple infarcts


    • Enhancement pattern is ring-like & gyriform


    • Gyriform T1 hyperintensity due to cortical laminar necrosis seen as early as 2 weeks post infarct


    • Contrast-enhancement of laminar lesions may be seen up to 8 months


Helpful Clues for Rare Diagnoses

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Aug 7, 2016 | Posted by in NEUROLOGY | Comments Off on Ring-Enhancing Lesion, Multiple

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