Intracranial dermoid cyst ruptured into the membranous labyrinth causing sudden sensorineural hearing loss: CT and MR imaging findings.

A ruptured dermoid cyst is rare and can present with various symptoms. We report imaging findings of an intracranial dermoid cyst that ruptured into the endolymphatic sac, causing sudden sensorineural hearing loss.

Anterior spinal artery as a collateral channel in cases of bilateral vertebral arterial steno-occlusive diseases.

BACKGROUND AND PURPOSE: We report 6 cases of retrograde flow through the anterior spinal artery (ASA) from cervical vertebral artery (VA) to intracranial distal VA because the perfusion from bilateral vertebral arteries was tenuous. Its hemodynamic and clinical implications are discussed. METHODS: In association with bilateral steno-occlusive disease of vertebral arteries, 6 cases of retrograde flow through ASA were reviewed in terms of clinical and angiographic characteristics. All 6 patients presented with stroke in the posterior fossa and underwent conventional angiography as part of diagnostic evaluation and/or therapeutic intervention. RESULTS: On the angiography, 2 patients showed bilateral VA occlusion, and the other 4 patients showed VA occlusion on 1 side and severe stenosis in the other VA. Distal perfusion by ASA was prominent in 2, and not prominent in 4. Reversal or disappearance of the retrograde flow through ASA was observed after successful recanalization of the occluded VA in 4 patients. In 1 patient, increased perfusion through ASA was observed because the stenosed VA was completely occluded. CONCLUSION: When the vertebral arteries were occluded bilaterally or when a single VA was occluded and the other carried a severe stenosis and, as a result, the basilar arterial blood supply was tenuous, retrograde flow through ASA could be observed. This is a potentially important source of collateral supply to the posterior fossa neural contents. The degree and extent of perfusion via this collateral channel varied depending on presence of other collateral routes and patency of the vertebrobasilar junction.

Successful endovascular occlusion of a ruptured distal anterior inferior cerebellar artery aneurysm of the caudal trunk: case report.

SUMMARY: We report a rare case of a ruptured distal anterior inferior cerebellar artery (possibly dissecting) aneurysm of the caudal trunk, successfully treated by endovascular occlusion. A 41-yearold man presented with sudden severe headache and drowsiness. On the day of ictus, conventional angiography was performed to make the above diagnosis, followed by endovascular occlusion of the sac and the parent artery. The patient recovered completely without any neurologic deficit after treatment. Endovascular occlusion could be a safe and effective treatment option in a case of a ruptured distal AICA aneurysm of the caudal trunk.

An angiographic lesion mimicking pseudo-aneurysm in cerebral arteriovenous malformation.

In cerebral arteriovenous malformations (AVMs), a pseudo-aneurysm represents rupture site, and its presence is known as a factor for rebleeding. We report a case of cerebral AVM presenting with intracerebral haemorrhage in which cerebral angiography showed a lesion mimicking pseudo-aneurysm. Although the patient needed urgent surgical decompression, it was delayed because early haematoma evacuation would induce rebleeding from the rupture site. The authors attempted to occlude the pseudoaneurysm interventionally before surgery. After surgical excision, the lesion that was believed to be a pseudo-aneurysm was revealed as a partially thrombosed venous sac having a thick fibrous wall. In this report, the authors discuss the pitfalls in the interpretation of pseudo-aneurysms in angiographic AVM architecture.

Multiple meningiomas of different pathological features: case report.

Meningioma is a common intracranial tumour and it may occur not infrequently as one of the multiple tumours, especially in patients with neurofibromatosis. The incidence of multiple meningiomas (MMs) without the stigmata of neurofibromatosis is rare, ranging from 1 to 9% of all meningiomas in the literature. Multiple meningiomas with different pathologic features are even rarer, and most of them are benign histologies. The authors report an extremely rare case of MMs which were presented with malignant and benign histological features simultaneously. The underlying mechanism of MM formation is still unclear, however, subarachnoid spread was thought to be the most likely mechanism. The findings of most of MMs showed identical histopathological features and several molecular biologic studies provided evidence for the monoclonal origin of MMs to back up the above hypothesis. However, different histological features among the reported multiple meningioma cases including our particular one, suggests their origin from multicentric neoplastic foci activated by a supposed tumour-producing factor. However, we cannot completely exclude the possibility of independent progression from monoclonal origin.

Epithelioid haemangioendothelioma of the sphenoid bone.

The authors report a case of cranial EH occurred in the left sphenoid bone that was totally excised without transfusion. A 26-year-old woman presented with a 1-year history of progressing exophthalmos in the left eye. A cranial X-ray showed a mixed osteolytic and sclerotic expansile mass lesion in the left sphenoid bone. Neuroradiologic imaging study revealed a left temporosphenoidal extra-axial expansile mass lesion with heterogeneous enhancement after contrast enhancement associated with destruction and erosion of the temporal and sphenoid bones. The cerebral parenchyma and orbital contents were compressed without any sign of infiltration. Bone scan showed hot uptake in the left orbital region. Angiogram demonstrated marked neoplastic angiogenesis from the middle meningeal artery and other branches of left external carotid artery, for which preoperative embolisation was tried in vain. Cranio-orbito-zygomatic approach was undergone in two stages because of the patient's religious belief (patient was Jehovah's witness) and profuse bleeding during the first surgery. Two weeks after initial operation, second surgery was carried out with total excision of the residual mass in the left orbital ridge. Histopathological examination revealed typical epithelioid cell cords or nests in myxoid stroma with a positive immunoreactivity to factor VIII-related antigen. The authors report an unusual case of EH involving sphenoid and temporal bone in a young woman. Preoperative embolisation is thought to be absolutely essential before removal. Because there is no convincing data to advise radiation/chemotherapy, total resection and close follow-up may be reasonable.

Hemangioendothelioma of the sphenoid bone: a case report.

Hemangioendothelioma is borderline or intermediate type of vascular neoplasm. Hemangioendothelioma is rare lesion that constitutes less than 0.5% of the malignant tumors of bone. We present a case of low-grade hemagioendothelioma of the skull in a 29-yr-old woman. She had pain, diplopia and exophthalmos of the left eye. Radiographic images showed a relatively well-demarcated, expansile osteolytic lesion with irregularly thickened trabeculae and calcifications in the left greater wing of sphenoid bone. Histologically, the tumor was an infiltrative vasoformative lesion. The vessels are generally well-formed with open or compressed lumina surrounded by endothelial cells showing mild atypia. It lacked frequent mitotic figures and severe atypia. Although excessive bleeding occurred during the operation, the mass was totally resected. Postoperative radiation was not necessary. She is free of disease and well 6 months postoperatively.

Expression of bFGF and VEGF in brain astrocytoma.

Neovascularization is an important factor in the prognosis of brain tumor and many angiogenetic factors have been evaluated for prognostic significance. Among them, basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) are known as potent angiogentic factors and mitogens. We evaluated seven cases of grade II brain astrocytoma. Four, group A, was diagnosed as anaplastic progression at their second operation, and three, group B, did not. Using monoclonal antibodies to bFGF and VEGF in paraffin embedded tissue from first operation, their immunoreactivity and differences between two groups were examined. The growth fractions of these tumor were also measured by Ki-67 monoclonal antibodies (MIB1). Immunostaining for bFGF in tumor cells were observed in both nuclei and cytoplasm, and for VEGF, mainly observed in the cytoplasm. Mean cell count number +/- standard deviation per high power field in each were as follows: 1) for bFGF, 20.08 +/- 6.38 in group A and 0.87 +/- 0.90 in group B (P < 0.01), 2) for VEGF, 43.75 +/- 17.09 in group A, and 0.8 +/- 1.06 in group B (P < 0.05) and 3) for the proliferation index with Ki-67 antibodies, 3.20 +/- 0.81 in group A and 0.77 +/- 1.03 in group B (P < 0.05). This data supports the assertion that angiogenetic factor such as bFGF and VEGF may contribute to progressive change of astrocytoma by tumor angiogenesis.

The rat 17 alpha-hydroxylase-17,20-desmolase (CYP17) active site: computerized homology modeling and site directed mutagenesis.

A homology model of the rat 17 alpha-hydroxylase-17,20 desmolase (CYP17) steroid binding domain was derived from the alpha/beta F supersecondary structural element of the 3 alpha/20 beta hydroxysteroid dehydrogenase (HSD) of Streptomyces hydrogenans that constitutes a major segment of the C19 steroid binding cavity. A CYP17 arginine-rich domain, including Arg346, Arg361 and Arg363, that has previously been shown to be important to CYP17 catalytic activity, is conserved in this HSD structural element between two HSD domains known to be important to C19 steroid binding. These two HSD motifs, in addition to a C-terminal domain at the apex of the steroid binding cavity, are also present in similar though not identical forms in the rat CYP17 sequence. The model was evaluated in terms of both hydroxylase/lyase activity and stability of CYP17 mutant proteins (Tyr334Phe, Phe343Ile, Arg357Ala, Arg361Ala, Asp345Ala), and further tested with mutagenesis of Glu353, Glu358, and Tyr431. Those amino acids located at folding junctions in the model steroid binding domain (Glu358, Arg361, and Tyr431) are each individually required to prevent degradation of the nascent protein, as well as for basic hydroxylase/lyase activity. Genomic analysis of the rat CYP17 gene reveals that this domain is contained in exon 6, and a correlation exists between the length of exon 6 and the boundaries of the HSD supersecondary element. These studies demonstrate that exon 6 of the rat CYP17 is essential for CYP17 activity, and may be structurally related to the NAD-linked prokaryote alpha/beta F supersecondary element.

A P-loop related motif (GxxGxxK) highly conserved in sulfotransferases is required for binding the activated sulfate donor.

A nucleotide binding motif termed the P-loop has been described for ATP- and GTP-binding proteins. The primary structure typically consists of a glycine-rich region followed by a conserved lysine. A related structure (GxxGxxK) noted in sulfotransferases has been suggested to be important for the binding of the cofactor 3'-phosphoadenosine-5'-phosphosulfate (PAPS), the universal sulfate donor for this class of enzymes. Using molecular techniques, point mutations that substituted alanines for the putative critical residues were introduced into the cDNA for estrogen sulfotransferase. The altered construct, although fully expressed by Chinese hamster ovary-K1 cells, demonstrated negligible enzymatic activity and failed to photoaffinity label with [35S]PAPS. In contrast, a construct in which three other amino acids in the region of the P-loop motif were similarly mutated retained activity and was photoaffinity labeled with [35S]PAPS. These data strongly support the notion that the P-loop motif found in all cloned sulfotransferases constitutes, at least in part, the PAPS binding site for these enzymes.