One test left, and the Cottages are fighting with each other. Foreman wants to test for sarcoma. Cameron protests that its markers would have also shown up in their sclerosis test and didn't, and then she and Foreman fight over whether the tumor cells looked like muscle or fat under the microscope. If they can't figure out a seemingly simple thing like that, then I don't think Ian has much of a chance here, guys. Chase sighs and says that he wants the final test to be for neurofibromatosis simply because "the other choices suck worse."
House takes a minute out of the sixty or so Ian has remaining in his life to sit at the kid's bedside. I guess he's committing Ian's face to memory, since he's figuring he'll be needing it for the next twelve years of obsession. Cuddy enters the room behind him, and House knows she's there before she even says anything. "You want me outta here?" he asks. "You come up with anything?" she asks, her insistence that he not work on or go near her patient worn down in the face of Ian's imminent demise. "No," House sighs. He leaves the room. Cuddy looks totally helpless. We see this look a lot on Cuddy when she takes House off cases and then has to solve them herself.
House and Wilson meet out on their shared balcony. House doesn't want to talk, but Wilson has great news to share: he won the poker tournament! Not too surprising, seeing as how only three people were playing in it and two of them were called away to do medical stuff. But anyway, apparently there was a fourth player named Berman and Wilson played him by sitting on his great cards and waited for Berman, figuring his opponent didn't have anything and wouldn't call him, to make a big bet. Wilson called Berman's all in and turned over pocket aces. "I nailed his ass!" Wilson says. I'm sure that he did. I hope his toenail polish didn't get in the way. House smiles at Wilson's victory and probably the mental image of Wilson nailing someone's ass, and then gets all serious because he has an Idea. "The aces were hiding all along," he mutters, cryptically.
House orders the Cottage to test Ian for Erdheim-Chester a second time. "The disease lied," he says. "Diseases don't lie!" Cameron says. EVERYBODY LIES, Cameron, even single-celled beings! When they did the colonoscopy on Ian, House says, the disease hadn't yet reached his GI tract (despite causing all that bloody diarrhea), and therefore it didn't show up. But it's there now. The Cottages don't want to waste their last test, but they don't have a choice either.