Monday, July 6, 2015

Case of the Week 356

The following images were taken from a brain biopsy of an immunocompromised patient with a mass lesion and mental status changes. Multiple organisms were seen around blood vessels and infiltrating adjacent brain tissue. These objects measure up to 20 micrometers in largest dimension.
 





Diagnosis?

8 comments:

Anonymous said...

Naegleria fowleri. Ingested RBC's in final frame?

Anonymous said...

N. fowleri.

Anonymous said...

I favor Balamuthia mandrillis or Acanthamoeba spp. causing "granulomatous amoebic encephalitis". The structures in the last image have refractory and round outer coats, making them look a lot like cysts. I wouldn't expect to see cysts in tissue if this was a case of Naeglaria fowleri, the cause of "primary amoebic encephalitis".

Anonymous said...

The initial "Anonymous" sez--I see--granulomatous amoebic encephalitis would be more likely in the immunocompromised host...

Anonymous said...

Agree with Balamuthia or Acanthamoeba

Anonymous said...

Naegleria fowleri has no cyst stage in tissue and can be ruled out.
The answers Acanthamoeba and Balamuthia mandrillaris are the possibilities. Size wise, these two amoebas are quite similar. Structurally, both do not have a peripheral chromatin, and this further complicates the differential diagnosis.
In the last picture,the cyst has a somewhat polygonal endocyst and does not appear to have a wrinkled outer wall characteristic of Balamuthia mandrillaris.
My best guess therefore is Acanthamoeba though it has been said many times "errare humanum est".

Florida Fan

Jeff and donna said...

Acanthamoeba!

Just me said...

Florida Fan,
Just curious about a comment in case 333, pertaining to MCV hg / hct levels ?