brain tumor q

[MudPhud20XX]

A 52-year-old woman has had right-sided headaches for 5 years, but has noted mild weakness in her left hand for the past week. On physical examination she has 4/5 motor strength of the left forearm, and 5/5 strength elsewhere. MR imaging of her brain is shown in the image. Which of the following neoplasms is this woman most likely to have?

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[suarad32]

Cystic frontal convexity meningioma? Pretty rare for these tumors to undergo cystic degeneration but its definitely well-circumscribed got a dural attachment and maybe a dural tail extending inferiorly and some enhancement of the bone (hyperostosis?). I'm not sure what the hypointense thing posteriorly is (meningiomas don't often bleed; could be a metastasis with a mural nodule but no systemic symptoms). GBMs can be cystic, but she wouldn't be symptomatic for five years (neither would mets).

 

[MudPhud20XX]

wow, good job man. i did not have any clue actually and wanted to hear other thoughts on this one. i did review pathoma but i dont think none of the clues from the question helped me get the answer. the only thing i can think is that the pt was a woman, but that's it. since meningioma is more common in women. what other clues from clinical symptoms are pointing to meningioma? or are supposed to know that well-circumscribed lesion is a big clue from the figure to come up with the diagnosis?

 

[suarad32]

Well, I take back the cystic part (I mixed up the T2 with the contrast sequence) but this is a simple meningioma. While its true that meningiomas have estrogen receptors, the biggest giveaway is the smooth non-infiltrating margins and the dural attachment. Hyperostosis of the overlying bone can occur as well.

Here's a quick algorithm off the top of my head (I only know this because I love neurosurgery and wrote a couple of papers on this but that was some time ago and so you may have to verify some of this):
Intra-axial (within parenchyma) supratentorial: glial tumors: GBMs (short history, older patients, can bleed postop), oligodendrogliomas etc. Pineal region neoplasms are frequently germ cell tumors.
Intra-axial infratentorial: Mets (unless proven otherwise in adults). Pilocytic astrocytomas or medulloblastomas (drop mets in cord) in kids: cerebellar mass +/- hydrocephalus. Hemangioblastomas if VHL-ish history or high hematocrit.
Extra-axial (outside parenchyma): meningiomas (often convexity, can be elsewhere; look for dural attachment or dural tail - enhancement along the dura beyond the attachment of the tumor. Schwannomas: trigeminal in the middle cranial fossa (Meckel's cave), vestibular in CP angle.
Extra-axial: midline sellar-suprasellar: Pituitary adenomas or craniopharyngiomas (cystic/calcified on CT). Similar presentation but cranios more often in kids. Rarely optic pathway gliomas in NF1 or tuberculum sellae meningiomas.
Extra-axial intraventricular: ependymomas (Tuberous sclerosis)/meningiomas/central neurocytomas (RARE!)

Hope this helps. I don't have time to cross-check this as Step 1 is in three days' time for me, but let me know if there are any mistakes!

 

[suarad32]

One correction: tuberous sclerosis gives you subependymal giant cell astroctyomas (SEGA) not ependymomas. The former looks like candle-stick drippings from the ventricles according to Goljan RR.

 

[seminoma]

Not ring enhancing.
Attached to dura/near convexity (versus deep like GBM).
Adult female.

Meningioma. Main thing imo is the homogeneous intensity.

 

[SBR249]

Based on the scenario and the imaging here are the clues I thought were important:

1) adult, middle aged which rules out the pediatric tumors like pilocytic astrocytoma

2) It's course. 5 year progression makes it unlikely to be an aggressive malignant tumor, plus the symptoms are all from mass effect.

3) It's relatively circumscribed, not multifocal, and separated from the parenchyma on the periphery right next to the bone

4) it's homogeneous on imaging

5) The large size, more aggressive and malignant tumors will kill the patient without treatment long before it reaches that size. Since meningiomas only cause mass effects, it can large to large sizes without overly compromising function and showing symptoms.

 

[seminoma]

I always thought meningiomas looked like fat epidural bleeds. If that helps.

 

[worldbeater]

A meningioma is the most intracranial tumor in the brain. So you know that off the bat, if the answer says meningioma "blah blah blah", that's most likely going to be it.

The most common primary brain tumor is an astrocytoma, while the most common primary brain cancer is an astrocytoma grade IV or glioblastoma multiforme.

It's better if you know the most common tumor/cancer of each organ (your basics) and then be able to apply it. Don't let a complicated question intimidate you.