Sunday, October 11, 2015

Answer to Case 367

Answer:  Echinococcus sp.

The main diagnostic features of this case are the characteristic protoscoleces with suckers and hooklets in a background of free calcified bodies (calcareous corpuscles).  Free hooklets are also present. The protoscoleces, calcareous corpuscles and free hooklets make up the material that is commonly referred to as "hydatid sand". Calcareous corpuscles are also seen in the stroma of each protoscolex. These calcified bodies are not unique to Echinococcus spp., but are found in all cestodes (larva and adults)

As many readers mentioned, this is most likely to be echinococcosis due to Echinococcus granulosus, since this is the most common species to infect humans. Yasir correctly notes that E. multilocularis rarely infects humans and almost exclusively involves the liver rather than the lungs.

Dima also notes that this could also be E. vogeli or E. oligarthrus, although these are both very rare in humans. Imaging studies would help differentiate cystic echinococcosis due to E. granulosus from alveolar or polycystic echinococcosis due to E. multilocularis and E.vogeli respectively.

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