This week's case was generously donated by Drs. Timothy Y. Chou and Roberta J. Seidman. The specimen is a corneal biopsy in an elderly woman who had been receiving ocular steroid treatment (but no systemic immunocompromising agents). The patient went on to develop bilateral punctate keratitis, and corneal biopsy showed the following objects:
H&E, 600x and 1000x
Tissue Gram stain, 1000x
12 comments:
The third picture suggests Toxoplasma. Again reading HE smear has never been my cup of tea and as such I can only guess.
Florida Fan
Corneal Microsporidiosis? CFW? mAFB? Mike
S. pneumoniae?
Complete guesswork, because I have no idea what I'm looking at with histological stains but....are these tachyzoites of Toxoplasma gondii?
Oh, and if I am correct, I suppose serology tests for Toxoplasma IgG and IgM would be appropriate.
Agree with Toxoplasma gondii. Appears to be bradyzoites. I would suggest IgM and IgA assays and IgG avidity test.
I believe they are Tachyozoites of T. gondii. Although looking as if they are encysted, I believe they are contained within individual corneal cells.
Cornea is not common site for Toxoplasma which mostly affected the posterior part of eye (choroid and retina) from systemic infection. The clinical manifestation, morphology and size of the organism on gram stain suggest microsporidia which pick up orange color and show belt structure. However there are some crescent shape suggesting Toxoplasma tachyzoite. Suggest for confirmation with PCR Toxoplasma and Microsporidia
Looks a bit like one of Microsporidia spp. Not sure. A trichrome stain would be more informative. Other organ systems may be involved in an immunocompromised patient as well.
Hi Dr. Pritt its Casey G. This is an interesting case. I agree with some of the previous comments. I think Toxoplasma or Microsporidia is a leading DDx, you could use a Toxo IHC (if that would be available) or I think PAS could stain the wall of Toxo. Acid-fast stain would help with Microsporidia. Other things that would be small and possibly intracellular could be Histo or Leishmania. GMS could be helpful in that context.
I like for microsporidia as these are clustering nicely and seem the right size and shape. Haven't seen for 20 years at the height of HIV. As a pathologist I'd approach with brute force and do electron microscopy, in part as microsporidia are very pretty ultrastructurally with the coiled filaments and in part don't have any specific stains or molecular tests sitting around.
I am also in favor of Toxoplasma.
I’d suggest to do a serology.
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