A past team member of mine had a client who kept telling providers that she "has worms in my brain." Multiple providers discounted the medical relevance of this individual's claims as delusions due to her schizophrenia-spectrum disorder and her low level of function.

My team member fought the providers like hell to get her an fMRI. Well the fMRI showed her brain was riddled with at that point inoperable tumors, and she died not long afterwards.

I'd heard other accounts of similar stories, but that was the first real-world example I had. If I had a client telling me there were ants in his belly, I'm not going to believe that's accurate, but I made damn sure we addressed it with providers.

People can describe physical symptoms in seemingly bizarre ways. Even if the exact scenario they are describing is clearly false, it doesn't mean they aren't experiencing very real physical symptoms.