Thymoma caused James Wilson’s terminal illness in House M.D. In the eighth season, Wilson learns that he has a rare cancer of the thymus and is expected to have only a short time left to live.
The diagnosis drives the final major arc of the series. Wilson initially continues working and tries to preserve normality, while House reacts intensely to the prospect of losing his closest friend. Their shared attempt to spend Wilson’s remaining time together forms the emotional center of the final episodes.
A thymoma is a tumor arising from the thymus, an organ located in the chest that plays an important role in immune-system development. The disease is uncommon, and its presentation in the show is part of the medical storyline rather than a claim that Wilson’s exact case represents every thymoma. Wilson’s diagnosis is often confused with other cancers seen in medical dramas, but the show specifically identifies it as thymoma.