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Teiji Tominaga, Hiroshi Shamoto, Hiroaki Shimizu, Mika Watanabe and Takashi Yoshimoto

✓ The histological changes that occur in brain tissue have rarely been documented in patients with dural arteriovenous fistulas (AVFs). In this study the authors report on two patients with dural AVFs in the transverse—sigmoid sinus who presented with subarachnoid hemorrhage or progressive dementia. Histological studies of the cerebellar cortices showed a selective loss of Purkinje cells, indicating an ischemic insult caused by venous hypertension. Admission N-isopropyl-p-123I-iodoamphetamine single-photon emission computerized tomography scans demonstrated a decrease in cerebral blood flow, including flow through the cerebellum. Venous hypertension caused by transverse—sigmoid sinus dural AVFs provokes an ischemic condition severe enough to cause selective neuronal damage in the cerebellum.

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Masayuki Kanamori, Toshihiro Kumabe, Mika Watanabe and Teiji Tominaga

✓The authors present the case of a 51-year-old man who presented with an anaplastic astrocytoma and anaplastic oligo-dendroglioma that developed 6 years after subtotal resection of a central neurocytoma in his right lateral ventricle. He had received neither radiation therapy nor chemotherapy after the original resection. On readmission, neuroimaging revealed a mass in the right parietal lobe and a diffuse lesion in the right temporal lobe, insula, and corona radiata. Because both lesions extended to the right lateral ventricle wall, they were regarded as recurrent rather than metachronous tumors. Histological examination revealed anaplastic oligodendroglioma in the parietal lobe and anaplastic astrocytoma in the insula. One year later, the anaplastic astrocytoma was found to have transformed into a glioblastoma multiforme. Fluorescence in situ hybridization analysis and immunohistochemical examinations detected deletions of the 1p36 and 19q13 loci, and nuclear accumulation of TP53 protein in the anaplastic oligodendroglioma but not in the glioblastoma multiforme. These findings suggest that central neurocytoma or progenitor cells have the potential for oligodendrocytic and astrocytic transformation with different genetic aberrations.

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Kuniyasu Niizuma, Miki Fujimura, Toshiyuki Takahashi, Akira Takahashi, Mika Watanabe and Teiji Tominaga

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Yui Mano, Toshihiro Kumabe, Ichiyo Shibahara, Ryuta Saito, Yukihiko Sonoda, Mika Watanabe and Teiji Tominaga

Dysembryoplastic neuroepithelial tumors (DNETs) have conventionally been regarded as benign and stable tumors and considered curable with surgery without adjunctive therapy. Recently, recurrent DNETs with or without malignant transformation have been described. The authors report 2 unusual cases of DNET: 1) an enlarging lesion that developed an enhancing component over the natural course of 4 years, and 2) a recurrent DNET that developed an enhancing component 10–11 years after gross-total resection. The patient in the first case was treated with subtotal resection and adjuvant radiochemotherapy; histological examination of the tumor led to the diagnosis of DNET, WHO Grade I, for the nonenhancing component and anaplastic oligodendroglioma, WHO Grade III, for the enhancing component. The patient in the second case was treated with repeat gross-total resection; the original tumor had been histologically diagnosed as DNET, and the nonenhancing and enhancing components of the recurrent tumor were diagnosed as simple and complex forms of DNET, respectively. These and previous reports suggest an aggressive subtype of DNETs. If follow-up MRI reveals progressive behavior, resection should be performed without delay. Additional radiochemotherapy is needed if the histological diagnosis demonstrates malignant transformation.

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Ryuta Saito, Yukihiko Sonoda, Toshihiro Kumabe, Ken-ichi Nagamatsu, Mika Watanabe and Teiji Tominaga

This 13-year-old boy with a history of cranial irradiation for the CNS recurrence of acute lymphocytic leukemia developed a glioblastoma in the right cerebellum. Resection and chemo- and radiotherapy induced remission of the disease. However, recurrence was noted in the brainstem region 8 months later. Because no effective treatment was available for this recurrent lesion, the authors decided to use convection-enhanced delivery (CED) to infuse nimustine hydrochloride. On stereotactic insertion of the infusion cannula into the brainstem lesion, CED of nimustine hydrochloride was performed with real-time MR imaging to monitor the co-infused chelated gadolinium. The patient's preinfusion symptom of diplopia disappeared after treatment. Follow-up MR imaging revealed the response of the tumor. The authors report on a case of recurrent glioblastoma infiltrating the brainstem that regressed after CED of nimustine hydrochloride.

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Ryuta Saito, Toshihiro Kumabe, Mika Watanabe, Hidefumi Jokura, Makoto Shibuya, Yoichi Nakazato and Teiji Tominaga

✓The authors report on a 21-year-old man who presented with a low-grade fibromyxoid sarcoma primarily located in the right parietal lobe with diffuse infiltration. The low-grade fibromyxoid sarcoma is a rare sarcoma of the deep soft tissue that is characterized as an indolent but metastasizing soft-tissue neoplasm with a deceptively benign histological appearance. Only one case of intracranial origin has been previously reported in the literature. A high rate of local recurrence and eventual metastasis has been demonstrated for this tumor in deep soft tissue. Similarly, the patient in the present case suffered recurrence 6 times; he underwent treatment by surgical removal 4 times, Gamma Knife surgery twice, and local radiation therapy once during the 7-year follow-up period. The tumor is still under control without any evidence of extracranial metastasis. To the authors' knowledge, this is the first case report that discusses the clinical course of this rare disease in detail.

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Yasuhiro Suzuki, Yasuko K. Yoshida, Reizo Shirane, Takashi Yoshimoto, Mika Watanabe and Takuya Moriya

✓ Reports of angiosarcoma arising in the central nervous system are rare. The authors present the case of a 30-day-old infant with clinical manifestations of projectile vomiting and tense anterior fontanelle resulting from a left frontotemporal tumor. Total excision of this highly vascular, well-circumscribed tumor was performed without incident, and histopathological examination revealed a malignant angiosarcoma. Immunohistochemical reaction of the neoplastic cells was diffusely positive for endothelium-specific antigens including factor VIII-related antigen, CD31, and CD34. The final diagnosis of congenital primary cerebral angiosarcoma was thus confirmed. The patient's postoperative course was uneventful, and he was discharged 2 weeks after the operation. He was in good condition with no sign of recurrence after 11 months; follow-up computerized tomography, magnetic resonance (MR) imaging, and abdominal ultrasonography studies demonstrated no tumor regrowth. The characteristic findings for this tumor on MR imaging, the immunohistochemical findings, and surgical outcome are discussed.

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Atsushi Kanoke, Masayuki Kanamori, Toshihiro Kumabe, Ryuta Saito, Mika Watanabe and Teiji Tominaga

This patient presented with a rare case of metachronous, multicentric gliomas first manifesting as headache and nausea in 1983 when he was an 8-year-old boy. Computed tomography revealed a cerebellar tumor and the tumor was subtotally resected. The histological diagnosis was pilocytic astrocytoma, and radiation therapy to the posterior fossa and chemotherapy consisting of nimustine hydrochloride and fluorouracil were performed. In 1989, at age 14 years, the patient presented with local recurrence. He underwent gross-total resection of the tumor, and histological examination revealed that the tumor consisted of classic pilocytic astrocytoma with a biphasic pattern and a small oligodendroglioma-like component. In 2011, at age 36 years, he presented with seizure. Magnetic resonance imaging revealed a mass lesion in the right middle frontal gyrus. Gross-total resection of the tumor was performed, and the histological diagnosis was oligodendroglioma. Genetic analyses revealed amplification of the BRAF gene in both the primary cerebellar pilocytic astrocytoma and the recurrent tumor with biphasic features, as well as a BRAF V600E missense mutation in the oligodendroglioma-like component. On the other hand, the IDH1 R132H mutation, instead of aberrations of the BRAF gene, was identified in the oligodendroglioma arising in the right frontal lobe. Different types of aberrations of the BRAF gene in the classic and oligodendroglioma-like component in the recurrent pilocytic astrocytoma suggest that they had different cell origins or that amplification of BRAF was negatively selected under the de novo BRAF V600E mutation. In addition, the aberration profiles of IDH1 and BRAF suggest that the oligodendroglioma arose independent of cerebellar pilocytic astrocytoma.

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Toshimi Aizawa, Tetsuro Sato, Yasuhisa Tanaka, Koshi Kishimoto, Mika Watanabe and Shoichi Kokubun

✓ Intraspinal plasma cell granuloma, which is a nonneoplastic entity, is extremely rare. To date, only four cases have been documented in the spinal meninges. The authors report the first case of a C7—T1 intramedullary plasma cell granuloma. After excision of the lesion, the patient's gait and bladder dysfunction improved. This plasma cell granuloma initially showed no delineated mass on T1-weighted magnetic resonance (MR) images, low signal intensity on T2-weighted images, and was well enhanced after administration of gadolinium diethylenetriamine pentaacetic acid. The latter MR imaging modality should help to detect this tumorous lesion. Histologically, the granuloma needs to be distinguished from lymphoplasmacyte-rich meningioma and plasmacytoma.

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Ayumi Narisawa, Toshiki Endo, Kenichi Sato, Mika Watanabe, Akira Takahashi and Teiji Tominaga

The authors report on a 49-year-old man with a thoracic spinal dural arteriovenous shunt (dAVS) in which rupture of a varix caused intramedullary hemorrhage. In the literature, patients with a thoracic dAVS predominantly present with congestive myelopathy; however, the patient featured in this report presented without increased deep tendon reflexes or muscle weakness, but instead with intermittent stabbing chest pain and paresthesia. Magnetic resonance images and angiograms demonstrated tortuous enlargement and the formation of a varix-like structure of the draining veins, features compatible with those of high-flow angiopathy. Recognition of this phenomenon is important in thoracic dAVS because intramedullary hemorrhage dramatically degrades outcome. A high index of clinical suspicion can prevent a similar case of thoracic dAVS from progressing to intramedullary hemorrhage.