There are times when you get a headache so powerful, the only explanation your pained brain can come up with is that you’ve got a cluster of squirming worms living inside your skull. As reported by Ars Technica, based on a case study published in the CDC journal Emerging Infectious Diseases, a guy in Spain learned that, no, it was in fact a bunch of worms in his head.The 60-year-old visited the doctor after suffering through two weeks of near-constant headache along with some subtle behavioral changes. A CT scan showed he had multiple lesions scattered throughout his brain, which led doctors to initially think that he had metastatic cancer. So, they launched a search for the tumor at the core of all this, which included tests like full-body scans and a colonoscopy. They ultimately found nothing. Good news, I guess, but still worrying.To get a better look inside the man’s head, doctors ordered a high-resolution MRI to get a clear view of the man’s brain. Turns out, the lesions weren’t tumors at all. They were fluid-filled cysts containing the larvae of Taenia solium, a tapeworm so commonly found in pigs that its more common name is “pork tapeworm.” They showed up so clearly on the MRI that the doctors could even make out the parasites’ little heads staring back at them.How Did the Worms Get in His Brain Though?Normally, when someone becomes infested with these worms, it’s because they’ve eaten undercooked pork. That usually happens in the intestines. This particular man’s condition, called neurocysticercosis, works a bit differently. In this case, the man likely ingested some microscopic tapeworm eggs, probably through food or water that had been contaminated by human feces, and then the larvae traveled through the bloodstream and got lodged in his organs, in this case, in his brain.Finding out you have brain worms can be a bit of a shock, but at least the discovery prevented an unnecessary brain biopsy from being ordered. Instead, all the doctors had to do was treat the man with antiparasitic medications, which he took and eventually recovered with no complications.The especially baffling part about the cases that the man was riddled with these worms while having never left Spain, where the condition is rare. The doctors could only guess how this happened, and they suspect that he may have been exposed years earlier through close contact with co-workers from places where the parasite is more common.The post Doctors Thought a Man Had a Brain Tumor. It Turned Out His Head Was Full of Worms. appeared first on VICE.