TERT promoter mutation associated with multifocal phenotype and poor prognosis in patients with IDH wild-type glioblastoma.

BACKGROUND: Although mutations in the promoter region of the telomerase reverse transcriptase (TERTp) gene are the most common alterations in glioblastoma (GBM), their clinical significance remains unclear. Therefore, we investigated the impact of TERTp status on patient outcome and clinicopathological features in patients with GBM over a long period of follow-up. METHODS: We retrospectively analyzed 153 cases of GBM. Six patients with isocitrate dehydrogenase 1 (IDH1) or H3F3A gene mutations were excluded from this study. Among the 147 cases of IDH wild-type GBM, 92 (62.6%) had the TERTp mutation. Clinical, immunohistochemical, and genetic factors (BRAF, TP53 gene mutation, CD133, ATRX expression, O 6-methylguanine-DNA methyltransferase [MGMT] promoter methylation) and copy number alterations (CNAs) were investigated. RESULTS: GBM patients with the TERTp mutation were older at first diagnosis versus those with TERTp wild type (66.0 vs. 60.0 years, respectively, P = .034), and had shorter progression-free survival (7 vs. 10 months, respectively, P = .015) and overall survival (16 vs. 24 months, respectively, P = .017). Notably, magnetic resonance imaging performed showed that TERTp-mutant GBM was strongly associated with multifocal/distant lesions (P = .004). According to the CNA analysis, TERTp mutations were positively correlated with EGFR amp/gain, CDKN2A deletion, and PTEN deletion; however, these mutations were negatively correlated with PDGFR amp/gain, CDK4 gain, and TP53 deletion. CONCLUSIONS: TERTp mutations were strongly correlated with multifocal/distant lesions and poor prognosis in patients with IDH wild-type GBM. Less aggressive GBM with TERTp wild type may be a distinct clinical and molecular subtype of IDH wild-type GBM.

[Natural History of Patients with Asymptomatic FLAIR High-signal Lesions Suspected of Lower-grade Gliomas].

The distribution of MRI scans has increased the chance of diagnosing asymptomatic FLAIR high-signal lesions. Herein, we retrospectively analyzed 14 asymptomatic FLAIR high-signal lesions to evaluate their natural course. Fifteen symptomatic(epilepsy)patients with FLAIR high-signal lesions were also analyzed as controls. As a result, all symptomatic patients underwent surgery and were diagnosed with lower-grade gliomas(n=14)and a dysembryoplastic neuroepithelial tumor(n=1). Among the 14 lower-grade gliomas, 11 gliomas were isocitrate dehydrogenase(IDH)-mutant. As previously reported, these results showed that FLAIR high-signal lesions with epilepsy are closely associated with IDH-mutant gliomas. On the other hand, 12 of the 14 asymptomatic patients showed no changes in the size of the lesion and symptoms during the follow-up period. Only 2 patients(14.3%)revealed increased lesions within 38 and 25 months, who were diagnosed with high-grade gliomas. Although there was no difference in the apparent diffusion coefficient value between asymptomatic and symptomatic lesions, low-intensity T1WI on MRI might be useful to discriminate lower-grade gliomas from non-tumor lesions. In conclusion, there is no need for immediate surgery for true asymptomatic lesions; however, we must undergo routine follow-up MRI scans.

Practical use of a simple technique, insertion of wet cotton pledgets into the tumor resection cavity in transsphenoidal surgery of pituitary tumors, for a better comparison between pre- and intraoperative high-field magnetic resonance images.

BACKGROUND: Intraoperative high-field magnetic resonance imaging (iMRI) is a useful modality for immediate intraoperative quality control. With iMRI, a surgeon can confirm whether tumor remnants exist during surgery; which makes it possible to add further resection, obtain a higher resection rate, and improve the cure rate. It is sometimes difficult to evaluate the existence of tumor remnants when the tumor resection cavity is collapsed. In this study, we reported a simple technique for comparing pre- and intraoperative MR images. PATIENTS AND METHODS: Thirty-five consecutive patients with pituitary adenoma underwent endoscopic endonasal transsphenoidal surgery using iMRI. Twenty-six patients had adenomas with suprasellar extension, and 9 had intrasellar adenomas. Nine adenomas had cavernous sinus invasion. Eight patients had endocrine-active, and 27 endocrine-inactive tumors. The simple technique included wet cotton pledgets inserted into the resection cavity to easily and precisely compare pre- and intraoperative MR images. Furthermore, we evaluated the efficacy of iMRI using our method on determining the extent of tumor resection in this study. RESULTS: The first iMRI scan showed that 12 of 35 patients had some tumor remnants, and 23 patients did not. Eight of these 12 patients with tumor remnants had cavernous sinus invasion. Three cases received further tumor resection after iMRI and had a gross total removal. CONCLUSIONS: We presented our initial results after using a simple method in high-field iMRI during endoscopic transnasal transsphenoidal pituitary surgery. This procedure allowed us to obtain valuable information to determine the extent of tumor resection and to precisely visualize the parasellar structures.

[Long-term outcomes of surgical treatment for epidermoid].

OBJECTIVE: Surgical strategies for epidermoids in our department is that the tumor capsule and surrounding arachnoid membrane should be sharply dissected and resected as much as possible. However, if total resection is not possible, because of the danger of surgical morbidity, partial resection should be carried out. The present study reports on long-term outcomes of surgical treatment for intracranial epidermoid in our department. METHODS: Since 1994, intracranial epidermoids have been resected in 13 patients in our department. The mean age at the time of surgery was 50.2 years and the mean postoperative follow-up period was 75.8 months. Surgical outcome, postoperative morbidity, Karnofsky Performance Status (KPS) during long-term follow-up, hydrocephalus, and regrowth rate were investigated. RESULTS: Among the 13 patients, 5 underwent total resection, 5 subtotal resection, and 3 partial resection. No permanent morbidity occurred and KPS did not worsen postoperatively in any of the patients. Surgery for hydrocephalus was performed in 3 patients. However, hydrocephalus had been suspected before surgery in each patient. Regrowth occurred in 1 patient, showing malignant transformation 1 year after total resection. No regrowth during long-term follow-up was observed in the other 12 patients, and none showed exacerbation of KPS. CONCLUSION: The present study indicates that regrowth does not necessarily occur in patients with epidermoids. Although total resection is ideal, to avoid any surgical morbidity is even more important. Partial resection should be performed if total resection is impossible.

Technical notes on endoscopic transnasal transsphenoidal approach for clival chondrosarcoma.

Although there are various operative approaches for clival tumors, a transsphenoidal approach is one of choices when the main tumor extention is in an anterior-posterior direction with a slight lateral extension. However, this approach sometimes provides only narrow and deep operative field. Recently, endoscopic transnasal transsphenoidal approach is quite an effective approach for clival tumors because of the improvement of surgical instruments, image guidance systems, and techniques and materials of wound closure. In this paper, we describe the effectiveness, technical problems, and solution of this approach based on our experiences with two clival chondrosarcomas that was removed by endoscopic transnasal transsphenoidal approach.

[Detection of acute subdural hemorrhage using intraoperative MR imaging during glioma surgery: a case report].

Intraoperative MRI (iMR) and neuronavigation have substantially changed the principles of surgery for brain tumors. iMR provides updated information on anatomical data and unanticipated brain events, thereby allowing safer and more accurate surgery. We herein report a case of unanticipated intracranial hemorrhage in an iMR imaging suite. The patient was a 53-year-old man with a chief complaint of generalized convulsion. MRI showed a lesion in the right temporal lobe about 6.0 cm in diameter. The tumor was resected using an iMR system and neuronavigation. The first iMR images showed a residual tumor in the medial temporal lobe. No brain events were detected at this time. We obtained updated navigation data and performed additional resection. After completion of the planned tumor resection, additional iMR images were taken. The second iMR images confirmed that the tumor had been completely removed, but they also revealed a contra-lateral subdural hemorrhage. After expedited closure of the original incision, left unilateral craniotomy was performed and the hematoma was evacuated. Fortunately, the patient had no new neurological deficits. The use of iMR imaging allowed the complete removal of the tumor and facilitated prompt and effective identification of an unanticipated life-threatening complication.

[Case report: spontaneous rupture of an asymptomatic intracranial dermoid].

We report a rare case of spontaneous rupture of an asymptomatic, intracranial dermoid cyst. A 64-year-old man complained of transient dizziness. MRI incidentally disclosed a 20-mm-diameter cystic lesion in the left cerebellopontine angle. Since the cyst was asymptomatic, follow-up MRIs were performed. One year later, sudden headache and left oculomotor palsy occurred. MRI showed niveau formation within the cyst and scattered fat droplets within the cerebrospinal fluid space, which indicated a spontaneous rupture of the dermoid cyst. Since hydrocephalus on MRI and gait disturbance appeared 2 months later, the tumor was resected, and a ventriculoperitoneal shunt was inserted. The patient's symptoms disappeared, and there were no postoperative neurological deficits. The pathological diagnosis was dermoid cyst. Only 48 cases of spontaneous rupture of a dermoid cyst have been reported. All were symptomatic, and MRI showed a large cyst. Of these cases, none was detected incidentally. Therefore, this is the first case report of an incidentally found dermoid cyst that ruptured spontaneously. Although asymptomatic, small dermoid cysts are usually followed up by MRI without surgical intervention. The possibility of spontaneous rupture, which may give rise to hydrocephalus, as in this case, should always be kept in mind.