| |||||||||||||||||||||
| |
|
Chordoid meningioma: A report of two cases Correspondence Address:
Chordoid meningioma is an uncommon histopathological variant of meningioma. We report 2 cases of chordoid meningioma occurring in adult patients.
Meningiomas are some of the most common intracranial tumors. The 1993 World Health Organization classification of CNS tumours described 14 distinct histopathological variants; chordoid meningioma is one of them. A literature survey till 2001 revealed that apart from 2 large series,[1],[2] the majority of the documented cases are individual case reports.[3],[4],[5],[6] In this report, we describe 2 additional cases of chordoid meningioma, highlighting the clinical, neuroradiological and light microscopic features.
Case 1 A 20-year-old male patient presented with a two-year history of severe bifrontal throbbing headache. In the month preceding presentation, he also had two episodes of generalized tonic-clonic seizures with loss of consciousness. Physical and neurological examination was unremarkable. Biochemical and hematological parameters were normal except for an elevated erythrocyte sedimentation rate (65mm/hr). Axial computed tomography (CT) of the brain [Figure - 1] revealed an isodense lesion with mild perilesional edema in the right frontal parasagittal region. Heterogenous enhancement was seen on post-contrast study. The patient was advised to undergo MRI of the brain to evaluate the exact nature of the lesion, but the patient refused further investigations. In view of the elevated erythrocyte sedimentation rate and the presence of heterogeneously enhancing lesion on imaging, a presumptive diagnosis of intracranial tuberculoma was made and the patient was treated with antitubercular therapy. The patient presented 3 months later with an increase in the frequency and severity of symptoms. CT of the brain was repeated and it revealed an increase in the size of the lesion as well as the degree of perilesional edema. Significant mass effect was noted on this CT study. The patient underwent a right frontal craniotomy for resection of the tumor. The lesion was seen as a firm globular mass which was adherent to the dura just lateral to the superior sagittal sinus. There was a well-defined gliotic plane around the tumor and the tumor could be easily separated from the brain surface. The tumor was excised in toto and sent for histopathological examination. The patient was asymptomatic during the one-year follow-up after surgery. CT study performed 6 months after surgery showed complete resolution of the edema without any residual mass lesion. Case 2 A 33-year-old previously healthy lady presented with 4 months history of bifrontal throbbing headache associated with vomiting. She also complained about episodes of blurring of vision and transient weakness of the left lower limb. On neurological examination, she was found to have bilateral papilloedema and right homonymous hemianopia. There were no other motor or sensory deficits. Hematological and biochemical investigations were within normal limits. CT of brain revealed a well-defined heterogenous hypodense mass lesion in the right frontal parasagittal region. The lesion had a broad base towards the anterior third of the falx cerebri. Heterogenous enhancement was seen on post-contrast study. Moderate perilesional edema was noted, causing mass effect with subfalcine herniation. The patient underwent a right pericoronal parasagittal craniotomy resection of the tumor. The mass seen in the parasagittal region along the anterior third of the falx was soft to firm in consistency. There was a well-defined plane of cleavage around the mass. Total excision of the lesion could be performed. Histopathological Findings The squash smears directly prepared from fresh tumor specimen during the intraoperative phase in both patients revealed the characteristic vacuolated cells [Figure - 2]. The frozen (cryostat) sections from fresh tissue showed an admixture of meningioma as well as the vacuolated cells, thus permitting a diagnosis of chordoid meningioma. The entire specimens obtained at surgery from both patients were subjected to light microscopic and immunohistochemical studies. In both cases, sections revealed sheets and lobules of epithelial-like cells which were seen scattered in a pale basophilic myxoid matrix [Figure - 3]. Some of these cells exhibited characteristic cytoplasmic vacuolization. Imperceptibly merging with these epithelial-like cells, were concentric whorl and lobule-like arrangements of cells which were characteristic of meningioma. In both cases, foci of lymphoplasmacytic infiltration were also seen. The specimen from the first patient also showed atypical nuclear changes with nucleolar prominence, occasional mitotic figures and focal nodular neural invasion. In both cases, the epithelial-like cells scattered in the basophilic myxoid matrix were immunoreactive for vimentin and epithelial membrane antigen. These cells showed negative immunostaining for glial fibrillary acidic protein. Based on the light microscopic and immunohistochemical staining characteristics, a histopathological diagnosis of chordoid variant of meningioma was made in both cases.
Kepes et al[1] for the first time, described a distinct meningeal tumor occurring in children and this was associated with systemic manifestations such as refractory microcytic anemia, hypergammaglobulinemia and angiofollicular lymphoid hyperplasia (Castleman Disease). Histopathologically, these tumors were composed of spindle or epithelial cells forming chordoma-like clusters and were scattered in a myxoid matrix. Prominent lymphoplasmacellular infiltration was also a feature in these tumors. Kepes et al also documented in their study, that administration of corticosteroids was usually associated with complete resolution of systemic manifestations and a significant decrease in the tumor volume. In a large series of 42 patients, Couce et al[2] observed that none of their cases had any systemic manifestations as reported by Kepes et al. The mean age of patients in the series of Couce et al was 44 years and hence they expressed the possibility that the systemic manifestations associated with this tumor are limited to chordoid meningiomas occurring in the childhood. The 2 patients described in this report were young adults and their main symptom was headache. The first patient also had episodes of generalized tonic-clonic seizures. There were no features suggestive of Castleman disease in either of our patients. Neuroimaging features in both our patients were more or less similar to that of typical meningiomas. However, in the first patient, the parasagittal location of the tumor gave a false appearance of an intra-axial lesion in the axial CT scan. In light of the elevated erythrocyte sedimentation rate, this was interpreted as a tuberculoma. Progression of neurological illness in this patient warranted a repeat CT study which revealed the features of a meningioma. Following a complete surgical excision, the patient became asymptomatic. CT scan performed at 6 months after surgery showed absence of edema and ruled out any residual lesion. The patient was on follow-up for 1 year and has not reported any episodes of headache or seizures. Both patients have been advised to present themselves for long-term follow-up. The precise diagnosis of chordoid meningioma can only be made with the help of an accurate histopathological analysis. Though the histopathological features are distinctive, these tumors should be distinguished from chordoma, chondrosarcoma and metastatic mucinous carcinoma. The identification of the classical meningioma component and the demonstration of membrane immunostaining in these tumors will establish the diagnosis of chordoid meningioma. However, difficulty in making the diagnosis can still be encountered, particularly for those tumors which arise from the base of the skull. In these cases, differentiation from chordoma may be extremely difficult. The recurrence rate in chordoid meningioma is reported to be very high. Couce et al[2] observed recurrence in all those tumors that were subtotally resected. A possible explanation for the high rate of recurrence could be related to the mucoid quality of its stroma which mechanically facilitates the spread of the neoplastic cells. This explanation is supported by the fact that all the recurrent tumors in their study were associated with a predominance of a mucin-rich chordoid pattern. Periodic follow-up and imaging studies after surgery are indicated if resection has been subtotal or if tumor recurrence is suspected on clinical grounds.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||