Cholesterol Granuloma Surgery

Cholesterol granulomas are rare, benign cysts that can occur at the tip of the petrous apex, a part of the skull that is next to the inner ear. The cysts are expanding masses that contain fluids, lipids, and cholesterol crystals surrounded by a fibrous lining.

Granulomas can occur throughout the body as a reaction to foreign material. They usually have no symptoms or serious effects. However, cholesterol granulomas of the petrous apex are dangerous because of their proximity to the ear and several important nerves. Permanent hearing loss, nerve damage, and bone destruction can occur if the mass is left untreated and continues to expand.

Cholesterol granulomas can form when the air cells in the petrous apex are obstructed. The obstruction creates a vacuum that causes blood to be drawn into the air cells. As red blood cells break down, cholesterol in the hemoglobin is released. The immune system reacts to the cholesterol as a foreign body, producing an inflammatory response. Associated small blood vessels rupture as a result of the inflammation. Recurrent hemorrhaging makes the mass expand.


The surgical approach depends on the location of the cyst and the status of the patient's hearing.   Surgery can be performed by a variety of approaches depending on the location and size of the lesion.  Surgery can be performed by approaches around the delicate structures of the inner ear, through a middle fossa approach above the ear, or via an endoscopic endonasal approach. 

Treatment involves drainage and ventilation of the cholesterol granuloma. In cases where the granuloma is particularly large and destructive, complete removal may be necessary. Access to the petrous apex is difficult and requires special surgical skills. The approach used depends upon the location of the mass, and the status of the patient's hearing.  Surgery usually requires an inpatient admission and hospital stay.