Saturday, June 29, 2013

Answer to Case 264

Answer:  Hooklets and protoscoleces of Echinococcus sp.

The free hooklets and protoscoleces with a stellate arrangement of hooklets is classic: 

Anonymous mentioned that "Many pathologists will miss this on real cases unless we see the scolices which stain!! We generally like flatter lower contrast microscopy and, forgiving poor nomenclatures, have our condensers relatively wide open."  It is true that traditional surgical pathologists will keep their condensers wide open to let in as much light as possible and may therefore not appeciate all of the refractile hooklets.  Therefore, I remind all of my residents and fellows that narrowing the condenser will bring out all of the features of hooklets, eggs, and arthropods in tissues.  It's a little 'trick' that I learned years ago. 

Aileen M Marty also reminds us that Ziehl-Neelsen will shown that many of the hooklets are acid-fast.  I wish I had a good example of this to show you.  If anyone would like to donate a case with acid-fast hooklets, I would love to share it!

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