Male character in his mid-forties is hospitalized showing symptoms for what doctors think is a terminal illness; it later turns out to be something curable/easily-treatable. Basically, I need an illness that a doctor could believably misidentify as a much more serious condition, and fit into the plot as well.
-The misdiagnosis has to be something that gradually progresses. Ideally, he would have at least a year or so to live. Alternatively, I could use a condition that is non-fatal, but is disfiguring or severely debilitating.
-The character would have to be hospitalized while all this happens, somewhere between a week and a couple of months. Either an observation stay after coming in with the symptoms or an unrelated injury that ends up revealing a problem (x-ray revealing a tumor etc.) could work.
I tried searching various permutations of "misdiagnosis," "terminal," and various fatal illnesses I could think of, but only really find cases of the reverse scenario.
Thanks in advance!