Spontaneous Regression of a Cholesterol Granuloma in a Mushroom-Like Extension Into the Middle Cranial Fossa After Tympanoplasty

Intracranial extension of a middle ear cholesterol granuloma is rare and typically requires invasive neurosurgical resection. This case is unique as it demonstrates spontaneous regression of a middle cranial fossa lesion following a minimally invasive transmastoid approach. A 41-year-old man presented with a suspected recurrent cholesteatoma. Magnetic resonance imaging (MRI) revealed a "mushroom-like" lesion extending into the middle cranial fossa, showing high signal intensity on both T1- and T2-weighted images without diffusion restriction, diagnostic of cholesterol granuloma. To minimize risk in the dominant hemisphere, we performed a transmastoid removal of the middle ear lesion and closed the bony defect with bone paté, leaving the intracranial portion. Postoperative MRI at four months confirmed complete disappearance of the intracranial lesion. Managing the middle ear environment and blocking the communication route could trigger spontaneous regression of intracranial cholesterol granulomas, providing a viable, less invasive alternative to direct intracranial surgery.