Answer: Trophozoites of Giardia lamblia(aka. G. intestinalis, G. duodenalis)
As many of you guessed, these organisms were most likely picked up in the duodenum when the endoscope was threaded through the small bowel to get access to the pancreatic cyst. I don't know of any reports where Giardia trophozoites actually inhabited a location other than the intestinal lumen.
This is really a beautiful example of the trophozoite morphology, and again, I'd like to thank Dr. Abdel Elhosseiny for this case. The giemsa stain nicely highlights all of the flagella which are not usually seen so clearly in a routine stool Trichrome stain.
Thanks to all for writing in with your comments!