Ian goes into the MRI of DOOOM! He fidgets a lot.
Out in the hall, Cameron is assigned to parent duty again. They don't understand why Ian is still being tested for stuff when he doesn't have that Erdheim-Chester thing. They also want to know what's going on in this other case they've heard talk of. So Cameron has to tell them that there was another case twelve years ago, but that they never figured out what was wrong with that patient. Because she DIED. I see Cameron is taking some baby steps towards delivering bad news; while she's not quite up to telling people that their family member has died, she is now able to tell them that someone else died twelve years ago. Go, Cameron!
Mom and Dad are called into the MRI booth to talk Ian through the MRI so that he'll stop fidgeting. Can't they just tie the kid down instead? That's so much easier, faster, and doesn't force us to watch a Sad, Poignant Moment of parents trying to reassure their kid that he'll be fine and hide the fact that they're just as scared as he is. "Mommy, are you crying?" Ian asks. She says she isn't, and she's right. No tears will fall from her eyes, because she's not a very good actress.
"Good coffee -- cheaper than Prozac!" reads the placard on the meeting room's coffee pot. Maybe so, but most of the people who use that room would probably be better off with some Prozac. Neither is available, though: the coffee pot is empty and so is the bag of grounds, much to House's displeasure. The Cottages rush in to report that they found a small mass on the base of Ian's brain, which seems to confirm the lymphoma diagnosis. Chase disagrees here, though, because the blood tests he just ran didn't show any lymphoma. So now we have a mass that will cause pituitary failure, just like what Ester had, but no lymphoma.
House leads the Cottages to the hospital coffee shop. It's closed for the night, but that won't stop House, who destroys the lock with a few well-placed whacks of his cane and helps himself to the freshly-brewed coffee the place apparently keeps on tap for any nighttime intruders. The next place Ian's mystery disease will hit, if Ester's example is correct, is the liver. House wants to start treatment to try to slow it down, but, as Cameron points out, they have no idea what they're treating him for. House loses it for a second and knocks some loud plates off the counter in frustration while he yells at them to "treat him for everything!" And since that never actually works and always makes the patient worse, I'm sure it will be a rousing success this time around.