Yoshimaru Ozaki

Careful exclusion of non-neoplastic brain components is required for an appropriate evaluation of O6-methylguanine-DNA methyltransferase status in glioma: relationship between immunohistochemistry and methylation analysis.

Evaluation of O6-methylguanine-DNA methyltransferase (MGMT) expression is important for antiglioma therapy as many clinical trials have demonstrated that promoter hypermethylation and low level expression of MGMT are associated with an enhanced response to alkylating agents. However, here we report that the current strategies used to evaluate MGMT status in gliomas are unreliable. We observed discordance in the MGMT expression status when immunohistochemical evaluation and polymerase chain reaction-based methylation assessments were used: 73% of gliomas with methylated MGMT promoter had substantial numbers of MGMT-immunopositive tumor cells. Furthermore, when MGMT expression was tested in tumor homogenates using reverse transcription-polymerase chain reaction, 43% of tumors were found positive, in comparison to only 24%, when histologic samples were assayed immunohistochemically. To explain these inconsistencies we undertook a detailed immunohistochemical evaluation of tumor samples and found that some gliomas demonstrated remarkably high expression of MGMT in the entire tumor whereas others contained only a small immunopositive area. Additionally, we found that gliomas contained various types of non-neoplastic cells expressing MGMT, including lymphocytes, vascular endothelial cells, and macrophages/microglias, which contribute to overall MGMT expression detected in tumor homogenates, and thus result in overestimation of tumor MGMT expression. Therefore, to correctly establish MGMT expression in the tumor, which could be informative of glioma sensitivity to alkylating agents, exclusion of non-neoplastic brain components from analysis is required.

JC virus large T protein transforms rodent cells but is not involved in human medulloblastoma.

JC virus (JCV) together with Simian virus 40 (SV40) and BK virus (BKV), belong to the polyomavirus group and these viruses are neuro‐oncogenic to rodents by expression of large T antigen (LT), which binds to cellular p53 and pRB thus reducing the anticancer potential of the cell. The function of LT has not been clarified because small t antigen (st) is transcribed from the same start codon as the overlapping reading frame of LT, and is translated as a different protein with the same N‐terminal residues (1–81 amino acids) by a splice‐site variant of mRNA. To elucidate the function of LT without st, we constructed plasmids that express LT only by deleting the splicing region including the C‐terminus of st, and consequently stable cell lines were established that express only JCLT, SV40LT and BKLT. The growth rates of these cells were examined in colonies on soft agar and it was found that LT alone has a transforming capacity; the order of efficiency being SV40LT, BKLT and JCLT. In addition, to verify the involvement of JCV in human medulloblastoma, eight cases of medulloblastoma, six cases of frozen material and five cases of paraffin‐embedded tissues which included three cases of frozen tissues, were examined. PCR assay, genomic Southern blotting, and in situ hybridization were applied to detect the JCV genome, and LT and st were examined by immunohistochemistry; the results were compared with JCV‐infected tissues as a positive control. All methods failed to detect not only JCV genome but also LT protein in medulloblastoma and it was concluded that JCV LT has transforming activities in rodent cells, but is not related to human medulloblastoma.

A case of cervicomedullary junction tanycytic ependymoma associated with marked cyst formation

Tanycytic ependymomas are a subtype of ependymomas that were formally recognized as a new pathological entity in the latest World Health Organization (WHO) classification of 2000. They occur mostly in the spinal cord. Only a few reports have analyzed the proliferative potentials of these tumors; however, it has been reported that the MIB-1 labeling index of tanycytic ependymoma is lower than that of other subtypes of WHO grade II ependymomas. We report a rare case of cervicomedullary junction tanycytic ependymoma associated with marked cyst formation. A 62-year-old man had a history of progressive gait disturbance, diplopia, and swallowing disturbance over a one-month period prior to admission. Magnetic resonance imaging (MRI) showed a cystic mass with a mural nodule at the cervicomedullary junction with Gd-DTPA enhancement. Cyst-subarachnoid shunt was performed using a far lateral approach. After 6 years, however, the man was readmitted to the hospital because of reaccumulation of the cyst. Partial removal of a mural nodule and a cyst-subarachnoid shunt were performed simultaneously by a midline suboccipital approach. The pathological diagnosis was tanycytic ependymoma. Postoperatively, the patient recovered well and was discharged from the hospital without further treatment. Most of the tumor cells had small, round nuclei; pleomorphism was minimal. The cytoplasm was dilated. The tumor cells were positive for EMA and s-100, and negative for CD-34. GFAP was not determined due to difficulty caused by background glial processes. The MIB-1 labeling index was less than 1%. Ultrastructurally, the tumor cells had ependymal cell features, such as desmosomes and microvilli. Based on these findings, the pathological diagnosis was tanycytic ependymoma.

Cerebral vasculitis in chronic mucocutaneous candidiasis : Autopsy case report

An autopsy case of chronic mucocutaneous candidiasis (CMCC) is reported here, in which cerebral vasculitis developed in the final stage. A 32‐year‐old man who had suffered from superficial candidial infection since his childhood was diagnosed as having CMCC. During the past 7 years the patient had developed various associated disorders including insulin‐dependent diabetes mellitus (IDDM), common variable immunodeficiency (CVID), candidial esophagitis, multiple digestive tract ulcers and pyothorax. In 1998, at the age of 32, he developed convulsions that were accompanied by impairment of consciousness, and which were temporarily treated with steroid pulsed‐medication. Epileptic status associated with widespread cerebral infarctions occurred subsequently, however, and the patient died of sepsis 2 months later. At autopsy, multiple cerebral infarctions and arterial thrombosis were evident. These were histologically proven to be primary vasculitis which was confined solely to the brain, and this was verified by general pathological examination. Thus, some as yet unknown cerebrovascular factors might be involved in the onset of an autoimmune‐related vasculitis in patients with a longstanding immunodeficiency state such as CMCC.

Clinicopathologic Study of Pineal Parenchymal Tumors of Intermediate Differentiation

OBJECTIVE Pineal parenchymal tumors of intermediate differentiation (PPTID) are extremely rare tumor entities, and only limited data are available regarding their pathologic features and biologic behaviors. Because grading criteria of pineal parenchymal tumors (PPTs) have yet to be established, the treatment strategy and prognosis of PPTIDs remain controversial. We describe the clinicopathologic study of six patients with PPTID and compare responses for the treatment and prognosis with cases of pineocytoma (PC) and pineoblastoma (PB). From this analysis, we attempt to clarify the treatment strategy for PPTIDs. METHODS This study included 15 patients with PPTs, consisting of 6 PCs, 6 PPTIDs, and 3 PBs. We focused on the 6 patients with PPTIDs. All PPTID cases were treated surgically, and radiotherapy and chemotherapy were administered as adjuvant therapies in some cases. We have earlier reported the histopathologic study (Neuropathology 32:647-653, 2012). Briefly, we examined mitotic figures and necrosis by hematoxylin-eosin staining and immunohistochemical markers such as neuronal markers (synaptophysin, neurofilament (NF), and neuronal nuclear antigen), and an MIB-1 labeling index was determined. RESULTS In the PPTID cases, the extent of resection was variable and the recurrence rates among patients varied according to stage and treatment. All PC patients underwent total resection with no recurrence. All PB patients underwent resection and adjuvant therapy with radiotherapy and chemotherapy. There were no recurrences in patients with PC or PB. The results of histopathologic findings have been already reported as mentioned above. Briefly, the results indicated no mitotic figure or necrosis in any of the six cases of PPTID, but those features were observed in PB cases. All cases even including PC and PB were immunopositive for neuronal markers. The MIB-1 labeling index of PPTID was 3.5%, whereas it was 0% in PC and 10.5% in PB. CONCLUSIONS Good radiosensitivity of PPTIDs was observed in our series. Because there are cases with discrepancies between images and pathologic findings, it is very difficult to determine the proper treatment strategy for PPTIDs. Proliferative potential was correlated with World Health Organization grade, although the immunoreactivity of neuronal markers did not correlate with the histologic grade.

A case of tanycytic ependymoma arising from the cerebral hemisphere

We report a rare case of tanycytic ependymoma arising from the cerebral hemisphere. A 59-year-old man was admitted to our hospital because of the incidental detection by MRI of a tumor lesion in the right temporooccipital paratrigonal region. The mass showed low-to iso-intensity on T1-weighted images and high intensity on T2/proton-weighted images. Partial resection was performed using a transsulcal approach to avoid compromising the visual field. Most of the tumor cells showed elongated spindle shapes arranged in dense fascicles. A few true ependymal rosettes and perivascular pseudorosettes were visible. The tumor cells were positive for GFAP, S-100, and vimentin, but negative for synaptophysin, EMA, and keratin. The MIB-1 labeling index was approximately 1%. Ultrastructurally, the tumor cells had ependymal cell features, such as microvilli and cilia. From these findings, a pathological diagnosis of tanycytic ependymoma was made.

Wernicke encephalopathy-like symptoms as an early manifestation of Creutzfeldt–Jakob disease in a chronic alcoholic

A case of Creutzfeldt-Jakob disease (CJD) with presenting Wernicke encephalopathy (WE)-like symptoms and severe insomnia is presented. An 80-year-old alcoholic man with a 6 month history of tremors, ataxia, memory loss and confabulation, developed profound insomnia, confusion, and delirium with vivid hallucinations. Polysomnography revealed a marked reduction of sleep time, with central-type sleep apnea. Neither myoclonus nor periodic synchronous discharge (PSD) was observed. An autopsy revealed diffuse spongiform changes and astrocytosis throughout the cerebral gray matter, with severe involvement of the mammillary bodies and thalamus. Prion protein (PrP) immunostaining was positive in kuru plaques in the cerebellum, PrP polymorphism at codon 129 was heterozygous Met/Val, and proteinase K resistant PrP (PrP(res)) was demonstrated by Western blotting. The lack of necrotizing lesions in the mammillary bodies, thalamus, and periaqueductal gray matter could rule out WE. The data suggest that the present case of CJD is consistent with PrP(res) type 2 (CJD M/V 2), but was unique in the lack of some typical CJD signs and the presence of signs of WE and sleep abnormalities.

A case of cerebral ganglioneuronal tumor in the parietal lobe of an adult

Central nervous system (CNS) neuroblastoma/ganglioneuroblastoma is one of the embryonal tumors with neuronal differentiation found in young adults, but it is most common in children, especially in those below the age of 5 years, whereas extraventricular neurocytoma, a rare neuroepithelial tumor with neuronal differentiation, mostly affects young adults. Here we present a rare case of cerebral ganglioneuronal tumor that occurred in a 32-year-old woman. The patient suffered from tonic convulsion, and computed tomography demonstrated a well-demarcated, round tumor 3.3 cm in size with marked calcification in the right parietal lobe. Histological analysis revealed diffuse infiltration of small, round cells with scattered large ganglion-like cells. Immunohistochemically, the tumor cells did not react with any neuronal molecules, except for chromogranin A in ganglion-like large tumor cells, but electron microscopy demonstrated the presence of synapse-like nerve terminal structures without mature postsynaptic density, suggesting the presence of neoplastic tumor components with neuronal differentiation; thus, this tumor was diagnosed as CNS ganglioneuroblastoma with possible low-grade malignancy because the Mib-1 labeling index was less than 3%–4%. Here we discuss the histological entity of cerebral ganglioneuronal tumors, including extraventricular neurocytoma.

Expression of O6-methylguanine DNA methyltransferase (MGMT) and immunohistochemical analysis of 12 pineal parenchymal tumors

Pineal parenchymal tumors (PPTs) are rare neoplasms which occupy less than 1% of primary CNS tumors. Because of their rare incidence, previous reports on PPTs are limited in number and the useful molecular markers for deciding histological grading and even selecting chemotherapy are undetermined. In this study, we conducted immunohistochemical analysis of 12 PPT specimens, especially for expression of O6‐methylguanine DNA methyltransferase (MGMT) to assess whether temozolomide (TMZ) could serve as a possible alternative therapy for PPTs. We analyzed 12 PPTs, consisting of three pineocytomas, six PPTs of intermediate differentiation (PPTIDs), and three pineoblastomas. Immunohistochemical analysis was performed using antibodies against MGMT, synaptophysin, neurofilament protein (NF), p53, and neuronal nuclear antigen (NeuN). Immunohistochemically, 11 out of 12 cases were positive for MGMT. The mean MIB‐1 labeling index was less than 1% in pineocytoma, 3.5% in PPTID, and 10.5% in pineoblastoma. All 12 cases were positive for synaptophysin and 11 cases, except one PPTID case, showed positive for NF. Nuclear staining of NeuN was negative in all cases although cytoplasmic staining of NeuN was observed in five cases. No case was positive for p53. Eleven out of 12 cases of PPTs demonstrated MGMT expression, suggesting chemoresistancy to TMZ treatment. This is the first report showing MGMT expression in PPTs. In addition, MIB‐1 labeling index correlated with WHO grade, although the immunoreactivity of synaptophysin, NF, NeuN and p53 did not correlate with the histological grade.

Radiation-induced osteosarcomas after treatment for frontal gliomas: a report of two cases.

Most radiation-induced osteosarcomas of the skull are reported to arise in the facial bone or paranasal sinus after radiotherapy for retinoblastoma and/or pituitary adenoma. Here we report two cases of radiation-induced osteosarcoma in the paranasal sinus after treatment for frontal glioma. Case 1 was a 56-year-old woman who underwent surgical resection of a left frontal tumor in October 1990. The histological diagnosis was a low-grade glioma, and radiotherapy of 54 Gy was administered. Sixteen years later, in September 2006, the patient noted an enlarging subcutaneous mass in the right frontal region. CT showed an osteolytic mass in the right frontal sinus. An open biopsy established the histopathological diagnosis of osteosarcoma, and the patient subsequently died of rapid tumor regrowth. Case 2 was a 58-year-old man who underwent partial removal of a bifrontal tumor in May 1996. The histological diagnosis was anaplastic oligoastrocytoma, and radiotherapy of 56 Gy was administered. Twelve years later, in March 2008, the patient was readmitted to our hospital for reasons of marked deterioration in general physical condition. Tumor recurrence was suspected in the left frontal lobe, and CT demonstrated an osteolytic mass in the left frontal and ethmoid sinus. A secondary operation was performed, and the pathological specimens were diagnosed as osteosarcoma. Radiotherapy was readministered, but the subject died of rapid tumor regrowth. From these clinicopathological findings, both cases were diagnosed as radiation-induced osteosarcoma. Radiation-induced osteosarcomas appeared 16 and 12 years after radiotherapy in cases 1 and 2, respectively. As the prognosis of radiationinduced osteosarcoma is poorer than that of primary osteo-sarcoma, careful attention is required for consideration of the long-term survival of patients with glioma.