Shintaro Fukushima

Revisiting TP53 Mutations and Immunohistochemistry—A Comparative Study in 157 Diffuse Gliomas

The association between p53 immunohistochemistry and TP53 mutation status has been controversial. The present study aims to re‐evaluate the efficacy of p53 immunohistochemistry to predict the mutational status of TP53. A total of 157 diffuse gliomas (World Health Organization grades II–IV) were assessed by exon‐by‐exon DNA sequencing from exon 4 through 10 of TP53 using frozen tissue samples. Immunohistochemistry with a p53 antibody (DO‐7) on paired formalin‐fixed paraffin‐embedded materials was assessed for the extent and intensity of reactivity in all cases. A total of 72 mutations were detected in 66 samples. They included 60 missense mutations, five nonsense mutations, four deletions and three alterations in the splicing sites. A receiver operating characteristic curve analysis revealed that strong p53 immunoreactivity in more than 10% of cells provided the most accurate prediction of mutation. Using this cutoff value, 52 of 55 immunopositive cases harbored a mutation, whereas only 14 of 102 immunonegative cases showed mutations, sensitivity and specificity being 78.8% and 96.7%. Tumors with frameshift mutations frequently showed negative immunostaining. Staining interpretation by an independent observer yielded comparable accuracy. We thus propose p53 immunohistochemistry as a moderately sensitive and highly specific marker to predict TP53 mutation.

IDH1/2 mutation is a prognostic marker for survival and predicts response to chemotherapy for grade II gliomas concomitantly treated with radiation therapy

Reliable prognostic biomarkers of grade II gliomas remain unclear. This study aimed to examine the role of mutations of isocitrate dehydrogenase (IDH1/2), 1p/19q co-deletion, and clinicopathological factors in patients with grade II glioma who were primarily treated with radiotherapy or chemoradiotherapy after surgery. Seventy-two consecutive patients, including 49 cases of diffuse astrocytomas (DA), 4 oligodendrogliomas (OL) and 19 oligoastrocytomas (OA), who underwent treatment from 1991 to 2010 at a single institution were examined. The overall survival (OS) of the DA patients (8.3 years) was significantly shorter than that of the OL and OA patients (11.7 years). IDH1/2 mutations were found in 46.9% of the DA patients and 82.6% of the OL and OA patients. The progression-free survival (PFS) and OS of the patients with IDH1/2 mutations (8.4 and 16.3 years) were significantly longer than those of the patients without IDH1/2 mutations (3.3 and 4.5 years). Among the patients with IDH1/2 mutations, those who were initially treated with chemoradiotherapy including nimustine hydrochloride (ACNU), had significantly longer PFS than those treated with radiotherapy alone, whereas no significant difference in PFS was observed between the chemoradiotherapy and radiotherapy groups in the patients without IDH1/2 mutations. Oligodendroglial tumors, age <40 years, initial Karnofsky performance status (KPS) ≥80, and IDH1/2 mutations were favorable prognostic factors regarding PFS and OS. IDH1/2 mutation was a predictive factor of response to chemoradiotherapy in grade II gliomas. Patients with IDH1/2 mutations may benefit more from chemoraiotherapy than those without IDH1/2 mutations.

TERT promoter mutations rather than methylation are the main mechanism for TERT upregulation in adult gliomas

observed TERT upregulation in some tumors without mutations in the hotspots. A small subset of tumors had neither TERT nor ATRX mutations [9]. Recently, it has been reported that DNA hypermethylation of the TERT promoter is a common finding in pediatric brain tumors and associated with TERT upregulation [2]. Hypermethylation of the TERT CpG island has been linked to increased expression levels in other cancers [2, 4, 5]. We, therefore, studied the association between TERT methylation and TERT mRNA levels to investigate the possibility that DNA methylation serves as an alternative mechanism for TERT upregulation in adult gliomas. Eighty-eight adult gliomas samples with known TERT promoter mutation status suitable for mRNA expression analysis, 43 of which had mutations, were examined in this study. TERT mRNA expression of 88 tumors including 48 primary glioblastomas that have previously been investigated was analyzed as described [1]. The methylation status of three regions within the CpG island (Regions 1–3; Fig. 1a), including the region methylated in pediatric tumors (Region 1) and the region that contains the two mutation hotspots (Region 3), was assessed by pyrosequencing of the PCR products amplified from bisulfitemodified genomic DNA. The methylation status was represented either as the mean methylation levels of all CpGs in each region or as a dichotomous variable (hypermethylated or unmethylated) at each region using the cut-off value of 15 % according to Castelo-Branco et al. [2]. More detailed information is available in Supplementary Materials and Methods. There was no significant difference in the mean methylation levels or the frequency of hypermethylated tumors in any of the regions between tumors of the different histological subtypes (astrocytic tumor, oligodendroglial tumor and glioblastoma), or between those with and without Telomere lengthening (TL) is mandatory for infinite proliferation of many cancer cells. This is generally achieved either by telomerase activation or in some cases by telomerase-independent alternative lengthening of telomeres (ALT) [3]. Recently, recurrent mutations at two hotspots termed C228T and C250T in the promoter region of TERT, a catalytic subunit of telomerase, have been reported in various types of cancers [1, 6, 7, 9, 12]. These mutations result in upregulation of TERT expression [1, 7], which is required for telomerase activation [11]. TERT promoter mutations are particularly common in adult gliomas [1, 9]. It is also known that a subset of astrocytomas harbors mutations of ATRX, which could lead to ALT [10]. We have previously shown that glioblastomas with TERT mutation had TERT mRNA upregulation [1]. We have also

Sensitivity and usefulness of anti-phosphohistone-H3 antibody immunostaining for counting mitotic figures in meningioma cases

According to current World Health Organization (WHO) criteria, counting mitotic figures (MF), which is equal to the mitotic index (MI), on paraffin sections stained with hematoxylin and eosin (HE) is one of the recognized classification methods for meningiomas. However, it is not always easy to find the area of highest mitotic activity, and there are different perspectives among pathologists with regard to differentiating MF from non-MF, i.e., which are apoptotic figures and which are crushed or distorted cells. Moreover, there is an issue of overgrading in meningiomas with preoperative feeder embolization. Recently, anti-phosphohistone-H3 (PHH3) antibody has been reported as a mitosis-specific marker for meningioma grading. In this study, we attempted PHH3 immunostaining for our meningioma cases and verified not only the sensitivity of PHH3 immunostaining but also that of its usefulness in grading meningiomas. Forty-five initial histologically confirmed meningiomas (37 benign, 7 atypical, and 1 anaplastic) were reviewed according to current WHO criteria based on counting MF on HE-stained slides. PHH3-immunostained MF were counted in the same way, and the MIB-1 labeling index (LI) was calculated for each sample. PHH3-labeled MF were easily identified and permitted rapid recognition of the areas of highest mitotic activity. As a result, significant increase of PHH3 mitotic index (PHH3-MI) in comparison with HE mitotic index (HE-MI) and strong correlations with HE-MI to PHH3-MI as well as PHH3-MI to MIB-1 LI were demonstrated. Furthermore, no significant differences of PHH3-MI between cases with and without feeder embolization were demonstrated. As such, PHH3 may be a sensitive and useful marker for meningioma grading as based on the MF.

Multinodular and vacuolating neuronal tumor of the cerebrum

Multinodular and vacuolating neuronal tumors of the cerebrum (MVNT) are superficial neuronal tumors in adults that were first documented in 2013. Herein, we report a case of MNVT involving a 37-year-old man who presented with an epileptogenic, superficial solid lesion in the left parietal lobe. Histomorphology of the resected specimen was characterized by nodular lesions with vacuolation. Nodules comprised irregular proliferation of neuronal cells, which ranged from ganglion-like forms to those with indistinct lineage. Immunohistochemical analysis showed that the lesional cells stained positively for HuC/HuD, synaptophysin, and Olig2, and negatively for NeuN, neurofilament, chromogranin A, GFAP, CD34, IDH1R132H, and BRAFV600E. Eighteen months following surgery, the patient is well and without neurological deficits. MVNTs are distinctive tumors that should be differentiated from ganglion cell tumors, dysembryoplastic neuroepithelial tumors, and malformation of cortical development.

Long-term follow-up of vanishing tumors in the brain: How should a lesion mimicking primary CNS lymphoma be managed?

OBJECTIVES The spontaneous disappearance of a tumor is referred to as a vanishing tumor. Most vanishing tumors in the brain are eventually diagnosed as malignant tumors or multiple sclerosis. However, their long-term clinical course remains unclear. This study aims to elucidate the management of vanishing tumors in the brain. PATIENTS AND METHODS We defined a vanishing tumor as a case in which the tumor spontaneously disappeared or decreased to less than 70% of the initial tumor volume before definitive diagnosis and treatment (other than steroid treatment). Ten cases of vanishing tumors are reviewed. RESULTS Nine patients underwent biopsy at least once. Five patients, all of whom had malignant tumors (primary central nervous system lymphoma: 4, germinoma: 1) that recurred in 4-45 months (median: 7 months), underwent a second biopsy after the reappearance of the tumors. Five patients (tumefactive demyelinating lesion: 1, undiagnosed: 4) who had no relapse are alive, and their median follow-up time is 44 months. No cases have yet been reported of malignant brain tumors that recurred more than 5 years after spontaneous regression. CONCLUSIONS Patients with vanishing tumors should be followed up carefully by magnetic resonance imaging for at least 5 years, even after the disappearance of an enhancing lesion.

Chordoid meningioma arising in the pineal region: a case report

We report a rare case of chordoid meningioma arising in the pineal region, which presented in a 22-year-old woman. Her only complaint was headache, and neurological examination revealed no deficits. She had suffered from prolonged fever a few weeks earlier, and her hematological findings included hypochromic microcytic anemia and a high serum level of C-reactive protein (CRP). Cranial magnetic resonance (MR) images demonstrated a 25 × 30 mm mass in the pineal region, which showed iso-to low intensity on T1-weighted images (T1WI), high to low intensity on T2-weighted images (T2WI), and homogeneous enhancement with gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA). We performed subtotal removal of the tumor with an occipital transtentorial approach (OTA), and all her preoperative symptoms completely abated. Histological examination of this tumor specimen showed the typical pattern of chordoid meningioma. Chordoid meningioma has been known to correspond with Castleman’s disease, and pineal meningiomas are extremely rare among intracranial meningiomas. The details of this case are presented with a review of the literature.

A case of more than 20 years survival with glioblastoma, and development of cavernous angioma as a delayed complication of radiotherapy

Glioblastoma (GBM) is the most common malignant CNS neoplasm, the prognosis of which remains poor even after multidisciplinary treatment. The 5‐year overall survival rate of GBM is less than 10% and has remained unchanged for more than 50 years. Because GBM patients rarely survive over a decade, only very few cases of delayed complications caused by therapy have been reported. Here, we report the case of a 24‐year‐old man who is still alive 21 years after surgical resection and chemoradiotherapy for GBM. This patient developed a cavernous angioma 19 years after the initial surgery as a delayed complication of radiotherapy. The diagnosis of the initial tumor was confirmed by histopathological review, which indicated that the tumor had immunohistochemical and genetic profiles consistent with GBM. Long‐term survival in the case of this GBM patient likely resulted from a combination of factors, including hypermethylation of the MGMT (O6‐methyl guanine methyl transferase) CpG island, young age at diagnosis, good performance status, and complete surgical resection of the tumor. To the best of our knowledge, this case report describes one of the longest‐surviving GBM patients and is the first on radiation‐induced cavernous angioma in a GBM patient.

Clinical presentation of anaplastic large‑cell lymphoma in the central nervous system

The majority of primary central nervous system (CNS) lymphomas are diffuse large B-cell lymphomas (DLBCLs) and anaplastic large-cell lymphoma (ALCL) is a type of T-cell tumor that is rare in the CNS. The aim of this study was to elucidate the clinical presentation and standard therapy of ALCLs by investigating reported cases. Additionally, a case of anaplastic lymphoma kinase (ALK)-positive ALCL in a 20-year-old man who exhibited no recurrence for >5 years following high-dose methotrexate (HD-MTX) treatment was described. Twenty-six immunocompetent patients with ALCL of the CNS that were previously reported and 1 case of ALCL of the CNS treated at our hospital were investigated. Overall survival (OS) was analyzed in relation to survival factors such as age, ALK status and the treatment regimen. The male:female ratio of the patients was 19:8. Of the 27 patients, 13 (48.1%) were ALK-positive, 9 (33.3%) were ALK-negative and the ALK status was not determined in the remaining 5 patients (18.5%). ALK-positive ALCL occurred at a younger age (median age, 17 years) and exhibited a favorable course (5-year OS, 75.0%), whereas ALK-negative ALCL presented at an older age (median age, 65 years) and resulted in fatal outcomes (5-year OS, <12.5%). Similar to the findings for systemic ALCL, ALK positivity, age <40 years and chemotherapy are associated with long-term survival for ALCL of the CNS. Chemoradiotherapy including methotrexate is recommended for ALCL and the possibility of treatment with chemotherapy alone for ALK-positive ALCL is currently under consideration.

Short communication: sclerosing meningioma in the deep sylvian fissure

Sclerosing meningioma is a rare type of meningeal tumor with extensive collagen depositions. Deep sylvian meningioma, a tumor that is unattached to the dura mater, is also unusual. The biological activity of both is controversial, as are therapeutic strategies. A heterogeneous contrast-enhanced mass in the right sylvian fissure of a 10-year-old boy with a 3-year history of epilepsy was identified via magnetic resonance imaging. The patient underwent partial surgical resection because the tumor was hard and contained numerous perforators arising from the right middle cerebral artery. The tumor was histologically diagnosed as sclerosing meningioma. Twelve months after surgery, the patient was asymptomatic and did not require any additional therapies. This case is the first report of a sclerosing meningioma arising in the deep sylvian fissure. We discuss the therapeutic dilemma of this case with respect to the current literature.