摘要To the Editor:Cholesterol granuloma (CG) refers to granulation tissue containing cholesterol crystals and giant cells and is a foreign body response elicited by local tissues.The pathogenesis of middle ear CG can be explained using the classic obstruction-vacuum theory caused by negative middle ear pressure.[1] The Eustachian tube (ET) plays a decisive role in influencing the gas exchange and maintaining the ventilation and pressure of the middle ear.The traditional treatment is mastoidectomy,routinely combined with middle ear ventilation tube insertion or tube insertion during re-examination after operation.[2] Eustachian tuboplasty by balloon dilation can improve the pathological state of ET via specific mechanisms to achieve functional recovery and satisfactory clinical efficacy.[3,4]