Medulla Lesion



Medulla Lesion


Nancy J. Fischbein, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Lateral Medullary Infarct


  • Wallerian Degeneration


  • Demyelinating Lesion (MS, ADEM)


  • Vascular Lesion



    • Cavernous Malformation; AVM


  • Brainstem Glioma, Pediatric



    • Diffuse Fibrillary Astrocytoma


    • Exophytic Cervicomedullary Glioma


Less Common



  • Brainstem Neoplasm, Adult



    • Glioma, High or Low Grade


    • Hemangioblastoma


    • Metastasis, Lymphoma


  • Vasculitis


  • Medial Medullary Infarct


  • Infection (Abscess, Tuberculoma, PML)


  • Syringobulbia


Rare but Important



  • Hypertrophic Olivary Degeneration


  • Infiltrative Disorders (Langerhans Cell Histiocytosis, Neurosarcoid)


  • Mitochondrial Disorder


  • Viral Encephalitis


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Acute onset of cranial nerve deficits and Horner syndrome in an older patient suggests medullary infarction



    • CT suboptimal for evaluation of medulla; MR with diffusion is indicated


    • Posterior circulation should be assessed intra- & extracranially with CTA or MRA


    • Vertebral artery dissection a consideration in younger patient; add Ax T1 with fat-sat


  • Reduced diffusion in focal medullary lesion usually due to acute medullary infarction


  • Volume loss of medullary pyramid(s) usually due to wallerian degeneration



    • Look for remote infarct


  • Expanded medulla? Neoplasm > infarction, demyelination, infection


Helpful Clues for Common Diagnoses



  • Lateral Medullary Infarct



    • Reduced diffusion; often subtle T2 abnormality in acute phase


    • Typically dorsolateral, due to occlusion of vertebral artery or PICA; check CTA or MRA


    • Wallenberg syndrome: Deficits in pain/temperature sense, dysphagia, hoarseness, vertigo, diplopia, Horner syndrome


  • Wallerian Degeneration



    • Acute wallerian degeneration may lead to medullary pyramid T2 hyperintensity, mildly reduced diffusion


    • Chronic infarction along corticospinal tract leads to volume loss of medullary pyramid; variable T2 signal


  • Demyelinating Lesion (MS, ADEM)



    • Usually associated with WM lesions in other parts of brain, may enhance, diffusion typically not reduced


  • Vascular Lesion



    • Cavernous malformation may be associated with developmental venous anomaly; GRE hypointense


    • CTA or MRA may help to evaluate for high flow vascular malformation


  • Brainstem Glioma, Pediatric



    • Diffuse infiltrative astrocytoma: Medullary expansion, ↑ T2 SI, usually nonenhancing


    • Pediatric astrocytoma may also be exophytic from cervicomedullary junction



      • Dorsal or ventral; often enhancing


Helpful Clues for Less Common Diagnoses



  • Brainstem Neoplasm, Adult



    • Medullary expansion, areas of irregular enhancement likely high grade glioma


    • Hemangioblastoma presents as nodular enhancement ± cyst



      • Usually in setting of VHL; look for other lesions in cerebellum, spinal cord


    • Focal enhancing lesion + associated edema: Consider metastasis, lymphoma


  • Vasculitis



    • Multifocal T2 lesions, variable DWI


    • CTA or MRA may show vascular irregularity, but catheter angiography generally indicated


    • Often associated with systemic symptoms, abnormal CSF


  • Medial Medullary Infarct



    • Less common vertebrobasilar stroke syndrome



    • Classic: Ipsilateral hypoglossal palsy, contralateral hemiparesis, contralateral lemniscal sensory loss


  • Infection (Abscess, Tuberculoma, PML)



    • Medullary pyogenic abscess rare; reduced diffusion, peripheral enhancement


    • Tuberculoma: Ring or nodular enhancement, central T2 hypointensity, diffusion variable


    • PML: Multifocal T2 abnormality, no mass effect, immunocompromised patient


  • Syringobulbia



    • Cervical syrinx may extend cephalad into medulla


    • Assess for Chiari 1 malformation, spinal cord tumor, other obstruction to CSF flow


Helpful Clues for Rare Diagnoses

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Aug 7, 2016 | Posted by in NEUROLOGY | Comments Off on Medulla Lesion

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