|Year : 2015 | Volume
| Issue : 3 | Page : 663
Chordoid meningioma: A diagnostic dilemma
Fouzia Siraj1, Mariya K Ansari1, KC Sharma2, Avninder Singh1
1 Department of Pathology, National Institute of Pathology, ICMR, New Delhi, India
2 Department of Neurosurgery, Safdarjung Hospital Campus, New Delhi, India
|Date of Web Publication||9-Oct-2015|
National Institute of Pathology, ICMR, Safdarjung Hospital Campus, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None
Chordoid meningioma (CM), classified as Grade II/atypical meningioma according to the World Health Organization classification, is a rare subtype, which represents only 0.5% of all meningiomas. Morphologically, it can mimic other chondroid and myxoid tumors within the brain and its vicinity thus posing a diagnostic challenge. Accurate diagnosis, therefore, assumes importance as these tumors have an aggressive clinical course and propensity to recur compared to classical meningiomas. Furthermore, the prognosis and treatment strategies vary when compared to tumors with morphological overlap. We present a case of CM in a 14-year-old girl and discuss its clinicopathological and immunohistochemical features.
Keywords: Chordoid, immunohistochemistry, meningioma
|How to cite this article:|
Siraj F, Ansari MK, Sharma K C, Singh A. Chordoid meningioma: A diagnostic dilemma. J Can Res Ther 2015;11:663
| > Introduction|| |
Meningiomas constitute approximately 30% of primary intracranial neoplasms and are known to have a broad spectrum of clinical manifestations and distinct histological subsets. Chordoid meningioma (CM) is a rare subset, representing about 0.5% of all meningiomas. These are graded as World Health Organization (WHO) Grade II tumors and are associated with a high likelihood of recurrence.  The term CM was first introduced by Kepes et al. in 1988  in a series of young patients with hematologic abnormalities especially Castleman's disease. However, subsequent studies failed to identify any association of CM with systemic manifestations. 
Histologically, chordoid variant is composed of cords or trabeculae of eosinophilic or vacuolated cells embedded in an abundant mucoid matrix. An accurate diagnosis of CM can sometimes be a diagnostic challenge because similar morphology can be encountered in other intracranial tumors such as chordoid glioma, chordoma, extraskeletal chondrosarcoma, myxopapillary ependymoma, and metastatic tumors.  A case report of CM is reported here, and its histopathological differential diagnosis is discussed.
| > Case report|| |
A 14-year-old female child presented with a history of frontal headache of 3 months duration. The headache had progressively worsened in last 1 month and was also associated with nausea and vomiting. Since last 2 weeks, she also complained of diplopia and blurring of vision in her right eye. There was no history of trauma, seizures, or loss of consciousness. Central nervous system (CNS) examination did not show any focal neurological deficit. Routine hematological and biochemical investigations were within normal limits. Magnetic resonance imaging (MRI) of the brain showed an intraaxial, well circumscribed, heterogeneously enhancing space occupying lesion in right superior parasagittal, frontal cortical and subcortical location. Perilesional edema with midline shift was observed [Figure 1]. A working diagnosis of meningioma was entertained.
|Figure 1: Preoperative magnetic resonance imaging T1-weighted image showing a well-circumscribed, heterogeneously enhancing space occupying lesion with perilesional edema and midline shift|
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A left frontal free bone flap craniotomy with complete excision of the tumor mass was performed, and the excised lesion was sent for histopathological examination. The postoperative recovery was uneventful, and there was no evidence of tumor recurrence in the postoperative computed tomography scan. No recurrence was noticed at 6 months follow-up.
| > Pathological findings|| |
Histopathological examination revealed that the tumor was composed of cords and trabeculae of round to polygonal cells having vacuolated cytoplasm, embedded in a prominent myxoid background [Figure 2]. Mild nuclear atypia was focally present. Owing to the absence of conventional meningothelial or transitional morphology, an immunohistochemical panel of antibodies was employed to reach diagnosis. Immunohistochemical staining showed positive staining for epithelial membrane antigen (EMA) [Figure 3] and D2-40 [Figure 4]a. The mean MIB-1 labeling index was 8% [Figure 4]b. However, the tumor cells were negative for glial fibrillary acidic protein (GFAP), S-100, and cytokeratin (CK). Based on these findings, a final diagnosis of CM (WHO Grade II) was rendered.
|Figure 2: Photomicrograph showing the tumor composed of cords and trabeculae of round to polygonal cells having vacuolated cytoplasm, embedded in a prominent myxoid background. (H and E, ×100)|
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|Figure 3: Immunohistochemical staining showing tumor cells to be positive for epithelial membrane antigen (×400)|
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|Figure 4: (a) Tumor cells exhibiting cytoplasmic immunoreactivity for D2-40 (×400). (b) MIB-1 labeling index is showing nuclear immunoreactivity (×400)|
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| > Discussion|| |
Chordoid meningioma is an uncommon variant of meningioma with a propensity for aggressive behavior and has increased likelihood of recurrence.  It was first described by Kepes et al.  in 1988 and was believed to occur mostly in young adults with various hematological abnormalities including hypochromic, microcytic anemia, and Castleman disease. Since then, the knowledge about this rare variant of meningioma has vastly improved, and no significant association has been found with any systemic disease. However, the aggressive nature of this tumor has been confirmed by various studies which warrant an accurate diagnosis. 
The incidence of CM ranges from 0.5% to 1% of all meningiomas. There is no age or sex predilection and the most common presenting symptom is headache. It is often located in the supratentorial region.  On MRI majority of cases have typical characteristics of meningioma, but definitive diagnosis of CM can only be made by histopathological examination.
Morphologically, CM consists of cords or trabeculae of round to flattened cells with eosinophilic or vacuolated cytoplasm and an abundant mucoid matrix background. Chronic inflammatory infiltrate, often patchy, may be prominent. Such chordoid areas are often interspersed with more typical meningothelial or transitional areas. The pure chordoid morphology is uncommon but can lead to a diagnostic dilemma when present exclusively. The differential diagnosis in this scenario includes tumors within or near the CNS exhibiting chondroid/myxoid appearance. These are chordoma, chordoid glioma, myxoid chondrosarcoma (skeletal and extraskeletel), low-grade chondrosarcoma, myxopapillary ependymoma, and mucinous metastatic carcinomas. , A thorough immunohistochemical workup with a panel of antibodies is required to differentiate between these tumors.
Among the tumors considered in the differential diagnosis of CM, chordoma is very important because of its striking histological resemblance to CM. EMA positivity in CM cannot alone differentiate it from chordoma as the latter is typically EMA/CK/S-100 positive.  Histological similarities also exist between chordoid gliomas and CM but lack of strong GFAP reactivity is useful in excluding chordoid glioma. Chondrosarcomas stain positively with S-100 while CM is usually negative for this protein. Similarly, strong EMA staining seen in CM is absent in most chondrosarcomas.  Myxopapillary ependymomas are almost exclusively located in conus medullaris, cauda equina, and filum terminale region and are GFAP positive. Metastatic lesions can mimic CM particularly renal cell carcinoma and mucinous carcinomas of the gastrointestinal tract. However, clinical and radiological correlation along with immunohistochemical panel for the primary tumor are often adequate for the correct diagnosis.
Recent studies have shown that D2-40, a monoclonal antibody initially developed against podoplanin is a selective marker of lymphatic endothelium and aids in identification of various benign and malignant tissues. Immunoreactivity with D2-40 antibody in CM is useful in the differentiation from both extraskeletal myxoid chondrosarcoma and chordoma. , Thus, a panel of antibodies comprising D2-40, EMA GFAP, and S-100 can distinguish CM from its histologic mimics as depicted in [Table 1].
|Table 1: Immunohistochemical profile in the differential diagnosis of tumors exhibiting chordoid morphology|
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Although some authors ,, have implicated the mucin rich, chordoid morphology for rapid enlargement and aggressiveness of CM, it has not been established as an independent prognostic feature. The most important prognostic factor in patients with meningiomas is the extent of resection. The recurrence rate after subtotal resection of CM is high.  However, complete resection may not be possible in large tumors, which are present near important functional areas of the brain or major blood vessels. Postoperative radiotherapy is recommended in such cases. , In the case reported here the patient was not considered a candidate for radiotherapy due to complete resection, absence of recurrence, and young age.
| > Conclusion|| |
Chordoid meningioma is a rare, aggressive subtype of meningioma which can morphologically mimic other tumors having chordoid/myxoid morphology. The pathologist should be aware of this rare entity due to its potential for aggressive biological behavior. A thorough immunohistochemical workup is required to diagnose this entity so that optimal tumor resection can be achieved for better patient management.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]