Chordoid meningioma, an uncommon variant of meningioma: a clinicopathologic study of 12 cases.

AIMS: The study has been undertaken to document the clinicopathological features of 12 cases of chordoid meningioma, operated at All India Institute of Medical Sciences during 1996 to June 2005.
METHODS: Clinical information was retrieved from the records of our Neurosurgery Department. The cases were stained with H&E, Periodic Acid Schiff (PAS) with and without diastase, mucicarmine, giemsa, toluidine blue, alcian blue, reticulin and Masson trichrome. Immunohistochemistry for pancytokeratin, epithelial membrane antigen, vimentin, glial fibrillary acidic protein, MIB-1, Leucocyte common antigen (LCA), CD-3 and CD-20 was done in all cases.
RESULTS: The age ranged from 12-67 years (mean 34.2 years) and three of them occurred in < 18 years. Male to female ratio was 1:1.4. The duration of symptoms varied from 3.5 months to 5 years (mean 14.1 months). No systemic symptoms were noted. The location of tumor in eight cases was in the supratentorial and rest four in the infratentorial compartments. Interestingly, two cases were in intraventricular location, one in the lateral ventricle and other in the fourth ventricle. Microscopic examination showed lobulation with chordoid elements constituting > 95% of the entire tumor area in 11 of the total 12 cases. In one case, chordoid pattern constituted about 30% of the total tumor area; the rest was predominant meningothelial (60%). Mild to severe lymphoplasmacytic cell infiltrate was present in all cases. The histochemical stains showed the pattern of acidic mucin and interestingly revealed the presence of mast cells both in connective tissue stroma and epithelial cell islands. The inflammatory infiltrate was B-cell predominant. MIB-1 labeling index was low (< 2%) in all cases except two, which showed LI of 6% and 8%. Strong diffuse immunoreactivity for vimentin and focal positivity for epithelial membrane antigen was noted in all cases.
CONCLUSIONS: Chordoid meningiomas are predominantly tumors of young adults with predilection for supratentorial location. Intraventricular location, absence of systemic manifestations despite the presence of abundant B-lymphocytes, presence of mast cells and low MIB-1 LI are some of the interesting findings in the present series, which need documentation. Hence, larger number of cases with adequate follow-up data need to be studied further to establish the clinical significance of this variant.