James Wilson is diagnosed with terminal thymoma near the end of House M.D.
Wilson is House’s closest friend and Princeton-Plainsboro’s head of oncology. In the final season, he learns that his thymoma has returned and that treatment cannot cure it. Doctors estimate that he has only a limited time left, which becomes the central medical and emotional problem of the final episodes.
Thymoma is a tumor originating in the thymus, an organ in the chest involved in immune-system development. The show uses Wilson’s diagnosis to shift the focus from solving a patient’s illness to confronting the limits of medicine and the value of friendship.
The storyline leads directly into the series finale, “Everybody Dies.” House ultimately abandons the appearance of his own death so he can spend Wilson’s remaining months with him.