Spontaneous Regression of Incidental Meningioma in the Posterior Cranial Fossa: A Case Report and Literature Review.

We report a rare case of spontaneous regression of a meningioma located in the posterior cranial fossa. A 60-year-old female patient presented with a headache. Both physical and neurological examinations were normal. Her medical history included type 2 diabetes mellitus. MRI showed a homogeneously enhancing mass in the left cerebellopontine angle. The volume of the tumor was 1.673 cm³. Radiological features, including the dural tail sign and the cerebrospinal fluid cleft sign, suggested the presence of a meningioma. Given these characteristics, we recommended serial follow-up MRI examinations. Unfortunately, the patient was lost to follow-up. Ten years later, she returned with a headache to reevaluate the previously diagnosed tumor. The follow-up MRI revealed significant regression and increased intratumoral calcification, with the tumor now measuring only 0.256 cm³. This report illustrates that meningiomas diagnosed incidentally can undergo spontaneous regression, a phenomenon that clinicians should be aware of.