This is quite an unusual case, that as Lukus Roberts mentioned, was published in JCM this past year:
We were first cued in the fact that this wasn't a real worm by the homogenous 'spongy' nature of the worm-like object. You can appreciate this best on cross-section:
It would be possible that a real worm of this size could be present in the bladder - for example, Dioctophyma renale, the giant kidney worm, or less likely, Ascaris lumbricoides - but a real worm would have discernable internal structures which were clearly lacking in this case.
The object was very resilient and didn't dissect apart, so we also didn't think it was any type of ureteral cast as mentioned by some of the viewers (although this is also a good thought and should be considered).
To work up the case, we first did touch preps of the object and tried to express eggs from it - all which only revealed a few urothelial cells and some bacteria. We also took a histologic section which showed amorphous eosinophilic material with no outer cuticle.
Fortuitously, we happen to have a jar full of rubber fishing worms that I had sent to the lab as an April Fool's joke 3 years prior. They had since been sitting in saline as part of our educational collection. When putting the patient's specimen and known rubber fishing worms side-by-side (both the saline-soaked specimen and 1 fresh from the package), it was clear that they were the same:
(the specimen that was in saline for 3 years is the middle worm, while the patient's specimen is on the right)
Closer detail of both ends of the 'worms'
Note the similar internal consistency of both:
To further characterize the nature of the specimens, we performed infrared spectrum analysis of the known fishing worm and the patient's specimen. The 2 spectra (shown below; patient on top) were indistinguishable:
Once we had this information, we discussed the case with the referring physician who then questioned the patient. At this time, the patient admitted to inserting the rubber fishing worm into his urethra approximately 3 years prior, but felt sure that the worm had been removed and was not retained in his urethra or bladder.
So a very interesting case! If anyone would like a copy of the manuscript, please send me a comment on this blog or a separate email (firstname.lastname@example.org) and I will send you a copy.