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Hello, welcome back to ProScan MRI Online.

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We are going to continue our discussion

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on non-glial CNS brain tumors.

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This patient is a 33-year-old man who presents with headaches.

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On the far left sequence is our sagittal T1

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weighted sequence, and we can see a relatively

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well-defined superior cerebellar mass

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with a striated appearance.

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The T1 signal is typically

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hypointense with striations.

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The T2-weighted signal is usually increased with

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these septate or striations throughout the lesion.

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And on the far right panel,

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which is our T1 post-contrast sequence, lesions

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typically have variable enhancement,

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usually do not enhance in my experience but can have

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increased vascularity in the molecular layer or the

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leptomeninges usually due to venous

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engorge or venous enhancement.

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These characteristics are most consistent with Lhermitte-Duclos disease or dysplastic cerebellar ganglioma.

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These tumors usually show increased cerebral blood flow

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and volume on perfusion-weighted imaging on spectroscopy,

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there's usually decreased NAA choline myo

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and can have a variable lactate peak.

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These lesions also demonstrate increased

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FDG uptake on PET imaging. So,

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Lhermitte-Duclos disease or dysplastic cerebellar ganglioma as

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we've described a relatively well-defined cerebellar

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masses with a striated or corduroy or thyrogyral form

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pattern which has thickened cerebellar folia and

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are usually infiltrative but are well demarcated.

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They are classified as a grade one tumor.

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They are always in the cerebellum,

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usually unilateral and sometimes involve the vermis,

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rarely involving the brain stem.

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They are considered a benign cerebellar lesion but it

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is unclear if it is neoplastic

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malformation or hamartoma.

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The non-proliferation or absence of malignant

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transformation favors a hamartomatous nature of the lesion

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associated abnormalities include multiple

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hamartoma syndrome or Cowden Syndrome.

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These lesions can occur most commonly between

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the ages of 20-40 years of age.

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There is no gender predilection and these lesions

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typically do not grow or grow only very slowly.

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If mass effect is not relieved,

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prognosis is extremely poor as these lesions.

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As you can see on this far-left sequence,

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there is some cerebellar tonsil herniation and these lesions

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can obstruct the fourth ventricle leading to obstructive

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hydrocephalus and herniation. So, in terms of treatment,

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this lesion can be surgically resected

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if the patient is symptomatic,

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typically consisting of debulking and shunting due to

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the possibility of hydrocephalus

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or obstructive hydrocephalus.

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Surgical resection can be difficult as you

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can see on the T2-weighted sequence.

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As this lesion bleeds into the adjacent parenchyma

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and the margins can be difficult to resect.

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Most common signs and symptoms for this lesion include

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headache, nausea, vomiting, papilledema, unsteady gait,

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upper limb dysmetria,

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blurred vision and lower cranial nerve palsies.

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Other signs could include sensory-motor deficits,

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vertigo and patients can even present in a coma

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given the mass effect upon adjacent structures.

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Lhermitte-Duclos disease has a very characteristic appearance

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and usually very little differential exists. However,

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in a certain setting of sepsis or

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acute clinical deterioration,

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differential considerations could include

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subacute cerebellar infarction. However,

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there'd be more mass effect,

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it'd be increased diffusion signal

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in a vascular territory.

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Cerebellar vasculitis would have an acute onset of

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symptoms but would have similar findings of surrounding

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vasogenic edema and mass effect and not a

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confined tumor. As we have in this case,

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associated syndromes with Lhermitte-Duclos disease or

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dysplastic cerebellar ganglioma include multiple

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hamartoma syndrome and Cowden Syndrome.

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Multiple hamartoma syndrome is an autosomal dominant

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disorder. Typically a mutation in the PTEN gene.

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Patients with these disorders develop hamartoma

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neoplasms of the skin 90 to 100% of the time mucosa GI

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tract bones, CNS, eyes, and the genital urinary tract.

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They are associated with an increased risk of malignancy.

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Cowden disease also has an increased risk

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of other neoplasms such as breast cancer,

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endometrial cancer, and thyroid cancer.

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If the patient is diagnosed with Lhermitte-Duclos disease,

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as in this case,

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then you must screen for multiple Hamartoma syndrome.

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If the patient is diagnosed with multiple Hamartoma

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syndrome, then you must screen for Lhermitte-Duclos disease.

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The long-term cancer screening is needed, especially for

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thyroid and breast cancer, as the increased risk of

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malignancy is increased in these syndromes

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and associations. In conclusion,

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this is a supercellular mass with your

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characteristic T2 hyperintense lesion with striations

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giving the corduroy or gyroid form pattern appearance

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consistent with Lhermitte-Duclos disease or

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dysplastic cerebellar ganglioma.