I went and tested this quest:
Handing in the
Fleshy Orb [Odd Tumor] to Priestess Caulria returns
Fleshy Orb [Odd Tumor Returned].
I attempted to troubleshoot what could have happened in your case and wasn't able to lose either orb by any means.
I attempted to hand in another Fleshy Orb [Odd Tumor] at the same time as a diseased wolf pelt, both items triggered the appropriate EVENT_ITEM and returned the correct item, stacked on the cursor.
I attempted to hand in Fleshy Orbs to nearby NPCs to see if they would eat it if accidentally handed the orb, and they returned it.
http://www.youtube.com/watch?v=wZCRiE-G0l4