Saturday, January 10, 2015

Answer to Case 332

Answer:  Taenia sp. proglottids

The 4 structures seen grossly are of the approximately size and shape that would be expected for Taenia proglottids, although they could represent non-parasitic structures as well.  Therefore, additional studies are needed for further characterization of these objects.  In the parasitology laboratory, we always try to examine possible proglottids using a dissecting microscope and look for characteristic structures and eggs.  For suspected Taenia proglottids, we also try to demonstrate the uterine branches so that we can determine the infecting species.

In this case, unfortunately, these proglottids were submitted for histologic sectioning and this limits the degree of identification that can be done somewhat. The presence of calcified stromal bodies called calcareous corpuscles allow us to confirm that these are cestode forms, while the eggs shown in some sections demonstrate a thick outer shell with radial striations which are consistent with Taenia sp.

However, these sections do not show the uterine branches and so the species of Taenia cannot be determined.

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