Evaluation of EZH2 expression, BRAF V600E mutation, and CDKN2A/B deletions in epithelioid glioblastoma and anaplastic pleomorphic xanthoastrocytoma.

INTRODUCTION: Epithelioid glioblastoma (EGBM) and anaplastic pleomorphic xanthoastrocytoma (APXA) are two rare entities with different prognoses. However, they share certain morphological and molecular features. MATERIALS AND METHODS: To better recognize EGBM and APXA and identify the prognostic factors associated with these tumors, EZH2 status, BRAF V600E mutations, and CDKN2A/B deletions were assessed in 15 APXA and 13 EGBM cases. RESULTS: The expression level of EZH2 was found to increase with tumor grade. Overexpression of EZH2 occurred in 69.2% (9/13) of EGBM cases and 20% (3/15) of APXA cases. In addition, 72.7% (8/11) of EGBM and 12.5% (1/8) of APXA cases harbored a CDKN2A homozygous deletion based on fluorescence in situ hybridization. BRAF V600E mutations were detected in 80% (8/10) of EGBM cases and 42.9% (3/7) of APXA cases. Furthermore, EGBM, which exhibited co-existing low-grade glioma-like lesions, was found to have strong EZH2 expression and high Ki-67 indexes only in epithelioid cells and not in low grade lesions. Univariate analysis demonstrated that abundant epithelioid cells, extensive necrosis, EZH2 overexpression and BRAF V600E mutations were significantly associated with decreased overall survival in EGBM and APXA patients (P < 0.05). CONCLUSIONS: The results suggested that testing for EZH2 expression and BRAF V600E mutations might be helpful to evaluate the prognoses of EGBM and APXA patients. The presence of heterogeneous EZH2 expression in biphasic EGBMs could also contribute to malignant progression.

Myxoma of the cranial base.

BACKGROUND: In 1871, Virchow described a type of tumor, which he named myxoma, which had a similar appearance to mucinous tissue of the umbilical cord. Myxoma occurs most frequently in the heart and jawbone, less frequently in the temporal bone mastoideum, and rarely in the cranial base of the brain. From an etiologic perspective, intracranial myxoma is divided into either primary or secondary induction. The majority of primary myxomas are found at the skull base, whereas secondary intracranial myxomas are mainly caused by metastatic tumor emboli from the cardiac myxomas; the emboli may also transfer to cerebrovascular endothelium to cause fusiform aneurysm. From October 1983 until November 2005, 23 patients with cranial base myxoma, as confirmed by pathology, were treated in the neurosurgery department of Beijing Tiantan Hospital. Few data are available from published literature on diagnosis and treatment of cranial base myxoma; therefore, the aim of this study was to describe a large series of patients undergoing treatment for cranial base myxoma and to analyze and discuss clinical manifestations, diagnosis, and treatment of cranial base myxoma. METHODS: A retrospective analysis was undertaken of 23 cases of cranial base myxoma, as confirmed by pathologic diagnosis. The review included all patients treated between October 1983 and November 2005. Among the 23, 8 patients received adjuvant radiotherapy after surgery. Postsurgical outcome data were unavailable for 12 patients. The mean duration of follow-up in the remaining 11 patients was 64.5 months. RESULTS: Tumors were commonly located at the middle fossa, parasellar, and jugular regions with characteristic calcification demonstrated with magnetic resonance imaging. Patients presented with headache and multiple lesions of the cranial nerves. Surgical approaches were variable and selected according to tumor locations. Partial resections were achieved in 16 cases and total resections in 7 cases. Complete relief of clinical symptoms was achieved in 2 cases, unchanged in 11 cases, and aggravated in 9 cases. During the period of follow-up, remission was gained in 6 cases and tumor recurrence in 4 patients; 1 patient died. CONCLUSIONS: Cranial base tumors are difficult to diagnose. By clinical features and neuroradiological findings, it is hard to distinguish myxoma from chondroma and chordoma in this region. Treatment results are seldom encouraging; the goal of complete surgical resection is rarely achieved, and the outcome of radiotherapy is not very successful.

[Myxoma of cranial base: study of 23 cases].

OBJECTIVE: To study the clinical manifestations and diagnosis and treatment of cranial base myxoma. METHODS: The clinical data of 23 cases of myxoma of cranial base confirmed by pathology from Oct. 1983 to Nov. 2005, 14 males and 9 females, aged 32.7 (18 approximately 50), were analyzed retrospectively. Operation was performed on all 23 patients, 8 cases underwent radiotherapy postoperatively. 11 patients were followed up after operation for 64.5 month. RESULTS: Most of the tumors were located in the parasellar and middle fossa and jugular region. The clinical manifestations included headache and injury of multiple cranial nerves. Imaging examination showed calcification and osseous elements in the center of tumor. The approaches of operation were selected according to the tumor position. Subtotal resection was achieved in 16 cases, and gross resection in 7 cases. The condition was improved postoperatively in 2 cases, unchanged in 11 cases, and aggravated in 9 cases, of which one died. The follow up showed that recuperation was achieved in 6 cases, recurrence occurred in 4 cases, and 1 patient died. CONCLUSION: It is hard to remove the total myxoma of cranial base. The curative efficacy of radiotherapy is not definite. The important substance of the myxoma is mucus. It is difficult to differentiate myxoma from chondrogenic tumor and chordoma in cranial base by the clinical and neuroradiological manifestations.