Tuesday, March 17, 2009

A teenager with tau-positive neurofibrillary tangles? What's going on?

Last week I wrote about the College of American Pathologist's neuropathology teaching cases. As an example of the kind of cases presented through this subscription, let me present to you photomicrographs from the most recent edition. Dr Roger McClendon from Duke (pictured above) provided a case wherein a teenager harbors cortical neurofibrillary tangles, vaguely evident in center of this H&E-stained slide:
The patient does not have Down's syndrome or any other reason to have Alzheimer's disease at this young age. And to prove that these are Alzheimer-like tangles, tau immunohistochemistry on the surgical specimen shows that these tangles are indeed tau-positive inclusions:
So? What's going on? See the comment to this post for the diagnosis and explanation.


Brian E. Moore, MD, MEd said...

The diagnosis is meningioangiomatosis. Usually a component of type 2 neurofibromatosis, this tumor exhibits an “en plaque” growth pattern along the cortical surface. An unusual feature of meningoangiomatosis is the presence of neurofibrillary tangles in adjacent neurons.(Source: Dr. Roger McClendon's answer explanation in the 2009 CAP Neuropatholgy Program Cases, Part A.)

Anonymous said...

Doesn't look like a teenager, but perhaps that's why he has the tangles.

Now my question: Although associated with NF2, it appears that only the sporadic forms are symptomatic. Is this true? If so, is it just a matter of NF2 patients getting scanned earlier, or is it that symptomatic MAs haven't been followed up? Both of these seem far-fetched, particularly based on the often quite young age at presentation of the symptomatic cases.

Brian E. Moore, MD, MEd said...

Where did you hear that only sporadic forms are symptomatic. I would imagine that trying to prove that would be next to impossible.

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