A case report on cystic meningioma in cerebellopontine angle and recommendations for management

Abstract

Rationale: Cystic meningioma located at the cerebellopontine angle (CPA) is an extremely rare occurrence. It is frequently misdiagnosed preoperatively. Little is known about the clinical features and outcome of this rare disease.

Patient concerns: A 70-year-old male presenting with progressive headache and gait disturbance.

Diagnosis: According to the symptoms, signs, and Gd-enhanced magnetic resonance images (MRI), a preoperative diagnosis of hemangioblastoma located in left CPA was made. Finally, the histological examination revealed a meningioma.

Interventions: A complete resection, including the part of the solid mass together with cyst, was performed.

Outcomes: The postoperative course of the patient was uneventful, and no residual or recurrent tumor was found during the 24-month follow-up period.

Lessons: Cystic meningioma should be included in the differential diagnosis of a CPA mass with atypical radiologic features, such as a large cyst and enhanced mural nodule. By summarizing the related literature, we found that the most common pathological subtype of CPA cystic meningioma is the clear cell subtype, which belongs to WHO grade II. Gross total resection including the enhanced cyst wall is extremely important. A close follow-up is necessary because of the high recurrence rate in this subset of meningioma.

Figure 1

Comparison of brain MRI of a 2-year interval. (A) Axial T1-, (B) T2-, (C) enhanced T1-, and (D) coronal enhanced T1-weighted MRI showed a broad based solid enhancing tumor with a multilobulated enhancing peritumoral cyst in the left CPA. (E) Axial T1-, (F) T2-, (G) enhanced T1-, and (H) coronal enhanced T1-weighted MRI of the same patient 2 years later showed a larger tumor especially an enlarged cyst and a fading enhancing rim of the cyst. MRI = magnetic resonance images, CPA = cerebellopontine angle.

Figure 2

Pathological findings. A, Meningothelial cells represented the majority of tumor stroma (HE, ×200). B, Immunoreactivity of progesterone receptor (PR, ×100). C, Epithelial membrane antigen (EMA) staining was positive (EMA, ×200). D, MIB-1 positive rate was less than 5% (MIB-1 × 200). In conclusion pathological findings indicate a meningothelial meningioma.