A Pediatric Case of Middle Cerebral Artery Dissection With Delayed Morphological Changes.

Middle cerebral artery dissection (MCAD) is a rare condition with no consensus on its treatment strategy and prognosis. This report describes a case of MCAD with perforating artery infarction in which radiographic findings progressed despite a lack of symptoms following maintenance infusion without antithrombotic therapy. A five-year-old boy presented to our hospital with right hemiplegia. Magnetic resonance imaging revealed diffusion restriction in the left basal ganglia. Additionally, magnetic resonance angiography (MRA) revealed irregular walls in the horizontal portion of the left middle cerebral artery. MRA performed three months after admission revealed progressive stenosis but no new ischemic lesions. MCAD can be associated with long-term morphological changes in the vessel walls. Intracranial artery dissection (IAD) in pediatric patients often presents without headache or neck pain, and serial imaging helps monitor disease progression. In conclusion, the morphology of the vessels can change over several months. Especially in pediatric patients, IAD often presents without headache or neck pain, and serial imaging evaluations help monitor disease progression.

KLC1-ROS1 Fusion Exerts Oncogenic Properties of Glioma Cells via Specific Activation of JAK-STAT Pathway.

Here, we investigated the detailed molecular oncogenic mechanisms of a novel receptor tyrosine kinase (RTK) fusion, KLC1-ROS1, with an adapter molecule, KLC1, and an RTK, ROS1, discovered in pediatric glioma, and we explored a novel therapeutic target for glioma that possesses oncogenic RTK fusion. When wild-type ROS1 and KLC1-ROS1 fusions were stably expressed in the human glioma cell lines A172 and U343MG, immunoblotting revealed that KLC1-ROS1 fusion specifically activated the JAK2-STAT3 pathway, a major RTK downstream signaling pathway, when compared with wild-type ROS1. Immunoprecipitation of the fractionated cell lysates revealed a more abundant association of the KLC1-ROS1 fusion with JAK2 than that observed for wild-type ROS1 in the cytosolic fraction. A mutagenesis study of the KLC1-ROS1 fusion protein demonstrated the fundamental roles of both the KLC1 and ROS1 domains in the constitutive activation of KLC1-ROS1 fusion. Additionally, in vitro assays demonstrated that KLC1-ROS1 fusion upregulated cell proliferation, invasion, and chemoresistance when compared to wild-type ROS1. Combination treatment with the chemotherapeutic agent temozolomide and an inhibitor of ROS1, JAK2, or a downstream target of STAT3, demonstrated antitumor effects against KLC1-ROS1 fusion-expressing glioma cells. Our results demonstrate that KLC1-ROS1 fusion exerts oncogenic activity through serum-independent constitutive activation, resulting in specific activation of the JAK-STAT pathway. Our data suggested that molecules other than RTKs may serve as novel therapeutic targets for RTK fusion in gliomas.

[A Case Report of Brain Metastasis from Anal Canal Carcinoma].

A 55-year-old female with adenocarcinoma of anal canal(stage IV with lung, bone, and lymph node metastasis)underwent total pelvic exenteration surgery and chemotherapy. Chemotherapy was continued after the surgery. One month later, she presented to the emergency room with gait disorder and cognitive dysfunction. CT and MRI demonstrated metastatic brain tumor in the right cerebellar hemisphere. Craniotomy and CyberKnife surgery were performed. Histological examination revealed adenocarcinoma with atypical cells forming a papillary arrangement. She died 35 weeks after the surgery. Brain metastasis from anal carcinoma is very rare, but recent advances in chemotherapy are achieving favorable results of long-term survival, and this is likely to increase in the future. Early detection, early treatment, and combined therapy may improve the long-term outcome for patients.

[A Case of Primary Intracranial Malignant Melanoma Mimicking a Traumatic Brain Contusion].

Primary intracranial malignant melanoma(PIMM)is a rare neoplasm of the central nervous system, accounting for 1% of cases of malignant melanomas and 0.1% of cases of brain tumors. Here, we report a case of PIMM that was initially considered to be a traumatic brain contusion. A 44-year-old man was transferred to a local hospital because of general tonic convulsion after falling while riding a bike. CT showed an irregular high-density area in the left temporal pole, which was diagnosed as a traumatic contusion. MRI performed 3 months after the initial episode revealed an enlarged temporal lesion with surrounding edema, suggestive of a neoplasm. The MRI showed the lesion as mixed signal intensity, suggesting both solid and cystic components. Subtotal resection was performed, except for the tumor adhering to the peripheral middle cerebral arteries(MCAs). The definitive diagnosis was made based on pathological findings and no evidence of extracranial lesions. Gamma knife surgery was performed for the remnant tumor adjacent to MCAs. The radiologically positive tumor chronologically regressed, and the patient remained progression-free for 18 months. Radiological findings of PIMM vary but typically include high density on CT and hyperintensity on T1-weighted MRI. Close observation enabled early diagnosis based on the suspicion of a neoplasm according to atypical radiological findings. PIMM has a poor prognosis with an overall survival of 12.0 months without confirmative treatment. Gamma knife surgery might achieve suppression of this highly progressive tumor.

[Hemifacial Spasm Caused by Vertebral Artery Fusiform Aneurysm and the Anterior Inferior Cerebellar Artery].

We report a case of hemifacial spasm in which the root exit zone(REZ)of the facial nerve was compressed by both the vertebral artery(VA)aneurysm and the anterior interior cerebellar artery(AICA). A 60-year-old female had suffered left hemifacial spasm for 2 years. Three-dimensional rotational angiography with selective arterial infusion of contrast medium(3DRA-IA)revealed that a distal part of the left AICA looping at the cisternal region was contacting the dome of the left VA aneurysm, although other imaging modalities did not show the exact course of the ipsilateral AICA. Constructive interference steady state magnetic resonance imaging revealed that both the left VA aneurysm and the left AICA had compressed the REZ of the left facial nerve. She underwent aneurysm clipping and decompression of the REZ by transposition of both the clipped aneurysm and the AICA using TachoSil®. Her hemifacial spasm disappeared immediately after surgery without complication. Some fine arteries might compress the REZ in patients with hemifacial spasm associated with VA aneurysms. 3DRA-IA was more effective for accurate evaluation than other imaging modalities. Transposition of vascular structures using TachoSil® is safe and effective for microvascular decompression surgery in such complicated cases.

[Three Surgical Cases of Brain Metastasis from Renal Cell Carcinoma Occurring more than 10 years after Nephrectomy:Case Reports and Literature Review].

Renal cell carcinoma(RCC)can metastasize to the brain within several years;however, 20 cases of brain metastases have been reported after>10 years of the initial nephrectomy. Here, we report three cases of brain metastasis that occurred>10 years after nephrectomy for RCC. In general, RCC is radio-resistant, but stereotactic radiosurgery has been reported to be effective in some cases. To improve the functional and survival prognoses, delayed brain metastases from RCC should be aggressively resected.