Clinicopathological analysis of metaplastic meningioma: report of 15 cases in Huashan Hospital

Abstract

Objective: Metaplastic meningioma is a rare subtype of benign meningiomas, classified as WHO grade I with well prognosis. Here we presented our experiences on 15 cases of metaplastic meningioma, to investigate the clinicopathological features, therapies and prognosis of these cases.

Methods: 15 patients underwent surgical treatment for intracranial metaplastic meningioma between 2001 and 2010 at Neurosurgery Department of Huashan Hospital, Shanghai, China. The clinical data, radiological manifestation, treatment strategy, pathological findings and prognosis of all patients were analyzed retrospectively.

Results: Among the 15 cases (10 males and 5 females), the age ranged from 22 to 74 years old (the mean age was 50.67-year old). The clinical manifestations include headache, dizziness, seizure attack, vision decrease, and weakness of bilateral lower limbs. All the patients received surgical treatment, combined with radiotherapy in some cases. In the follow-up period, recurrence occurred in 2 cases, of which 1 patient died of other system complications.

Conclusions: Metaplastic meningiomas are characterized by focal or widespread mesenchymal differentiation with formation of bone, cartilage, fat, and xanthomatous tissue elements. Surgical removal is the optimal therapy, and the overall prognosis is well. But recurrence may occur in some cases, thus radiotherapy is necessary for such kind of patients.

Keywords: Metaplastic meningioma; follow-up; mesenchymal differentiation.

Figure 1

No. 4 case of giant right ventricular metaplastic meningioma. A. Axial head CT scan revealing a giant right ventricular mass with high density and calcification in case 4; B. The tumor was mostly isointense in TI-MRI, but part of it was hypointense; C. The tumor was a little hyperintense in T2-MRI; D-F. After the administration of contrast, the lesion demonstrated obvious enhancement, but part of it wasn’t enhanced; G-H. Follow-up MRI obtained after operation showed no tumor recurrence

Figure 2

Histopathological findings of case 10. A. Tumor tissue contained large fat-like proliferation with conventional meningothelial neoplastic cells. Tumor cells have round nuclei and fat vacuole in cytoplasm in case 10 (H&E, original magnification ×40); B. The tumor cells were positive for EMA (original magnification ×40); C. The tumor cells were negative for GFAP (original magnification ×20); D. MIB-1 labeling index was less than 1% (original magnification ×40)

Figure 3

Histopathological features of SMA positive meningioma in case 2. A. Tumor tissue contained much smooth muscle-like tissues in case 2 (H&E, original magnification ×40); B. The tumor cells were positive for EMA (original magnification ×40); C. The tumor cells were positive for SMA (original magnification ×40)

Figure 4

Histopathological findings of metaplastic meningioma with osseous tissues. A. Tumor tissue contained areas of calcification and ossification in case 4 (H&E, original magnification ×40); B. The tumor cells were positive for EMA (original magnification ×40)