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Y Nakasu

Publications and source records attributed to Y Nakasu.

At least 37 records · Page 2Linked to original sources
PubMed1993

[Ossification and calcification of the cervical ligamentum flavum--case reports].

Ossification of ligamentum flavum was reported usually lower thoracic and lumbar region, and rarely seen in the cervical region. Calcification of cervical ligamentum flavum is also relatively rare. We report a case of ossification and another of calcification of cervical ligamentum flavum, and discussed the difference of the clinical and radiological features in these conditions. Case 1: A 55-year-old man presented with numbness of the left shoulder and urinary dysfunction. Neurological examination revealed weakness, muscle atrophy and elevated deep tendon reflexes of the left extremities. CT showed ossified mass protruding into the right side of the canal and compressing the spinal cord at C 3/4 and C 4/5. MRI showed low intensity mass both on T1- and T2-weighted images and severe compression of the spinal cord. Left side partial hemilaminectomy with foraminotomy, so called "key hole" foraminotomy, satisfactorily decompressed the cord with clinical improvement. Case 2: A 70-year-old woman complained numbness of both hands for two years. She had sensory disturbance of both hands and spastic gait disturbance. Cervical X-ray films showed calcified nodules on the inner surface of lamina at C4/5. Axial CT demonstrated calcification in the ligamentum flavum at the C4/5 and C5/6 levels. MRI showed posterior spinal cord compression at the C4/5 and C5/6 levels. Osteoplastic laminotomy and removal of the affected ligamentum flavum were performed with successful result. Only 8 cases ossification of cervical ligamentum flavum above C6/7 have been so far reported. All are Japanese; four male and four female cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Intramedullary subependymoma with neurofibromatosis--report of two cases.

Two cases of subependymoma in the cervical spinal cord associated with stigmata of neurofibromatosis are reported. Magnetic resonance (MR) imaging showed one tumor with a sharp margin, which was well-demarcated intraoperatively and was totally removed. MR imaging showed the other tumor with an irregular margin, which was partly invasive at operation. Subependymomas are rare in the spinal cord and these are the first reported associations with neurofibromatosis.

Adolescent↗
PubMed1991

Diploic meningioma contiguous to a contralateral parasagittal meningioma: CT and MR features.

A patient with a diploic meningioma is presented. Computed tomography (CT) scan revealed an intradiploic tumor which seemed contiguous at a point to a contralateral, recurrent parasagittal meningioma. On CT, density of the diploic meningioma was similar to that of the parasagittal meningioma, but the contrast study showed that the former enhanced much less than the latter. Magnetic resonance (MR) imaging demonstrated that the diploic tumor was heterogeneous and much less enhanced with Gadolinium-DTPA (Gd-DTPA) than the parasagittal meningioma on T1-weighted image, although they were very similar in signal intensities on T2-weighted and proton density-weighted MR images without Gd-DTPA. Reasons for such marked differences in enhancement patterns are discussed.

Female↗
PubMed1991

Mechanism of mutism following the transcallosal approach to the ventricles.

Transient mutism has been known as a common manifestation following callosotomy for medically intractable epilepsy, but its cause has not been clearly elucidated. In this paper, we report three cases of mutism following a transcallosal approach to tumours in the lateral and third ventricles and retrospectively analyze the surgical, neurological and radiological features which may suggest the cause of this type of mutism. Mutism may be a result of division of the corpus callosum. Suppression of the limbic system caused by lesions in the anterior cingulate gyrus, septum pellucidum, and fornix may have been of importance in at least two of these three cases. Impairments of the supplementary motor cortex, thalamus and basal ganglia may also be factors reducing speech production. The mechanism of such transient mutism seems to be a complex of two or more of these factors, and their combinations may be different from one case to the other.

Adult↗
PubMed1990

Periventricular spread of malignant lymphoma: report of two cases.

Two cases of intracranial malignant lymphoma with an atypical feature on CT scan are reported. Both patients presented subacute progressive dementia. CT scan showed high density lesion extending all the way along the ventricular wall, which was homogeneously enhanced and resembled severe ventriculitis. Differential diagnosis on CT scan is discussed.

Aged↗
PubMed1990

Central neurocytoma: report of a case.

Central neurocytoma is a rare intraventricular tumor recently accepted as a clinicopathological entity. A 21-year-old female was admitted with three-year history of episodic headaches and vomiting, and with rapid deterioration of her left vision over two weeks prior to admission. Computed tomography (CT) scan revealed a marked hydrocephalus and an isodense, mildly enhancing mass in the left lateral ventricle. On magnetic resonance imaging (MRI) scan, T1-weighted images revealed an intraventricular mass of slightly high intensity signal, which contained areas of low intensity signal representing multiple intratumoral cysts. The tumor showed a minimal enhancement with Gd-DTPA. A diagnosis of central neurocytoma was confirmed by an electron-microscopic study of a surgical specimen; there were numerous neuronal cell processes containing microtubules and dense-core vesicles, and a few small intercellular junctions were also identified.

Adult↗
PubMed1990

Vasopressin antagonist in early postoperative diabetes insipidus.

23 patients without diabetes insipidus before transfrontal (hypothalamic) or trans-sphenoidal (pituitary) surgery were studied prospectively to investigate the pathogenesis of early postoperative diabetes insipidus. 12 patients who underwent trans-sphenoidal surgery and who did not develop diabetes insipidus were used as controls. All received prophylactic corticosteroid replacement. Blood samples were obtained immediately after operation, at the onset of diabetes insipidus, and 24 h later. Immediately after trans-sphenoidal pituitary surgery, plasma vasopressin (AVP) was raised but had fallen to subnormal concentrations by the onset of diabetes insipidus. After transfrontal hypothalamic surgery diabetes insipidus occurred sooner and was associated with high plasma AVP immunoreactivity--but the plasma showed no antidiuretic bioactivity and greatly attenuated the antidiuretic response to standard AVP. Early diabetes insipidus after hypothalamic surgery is associated with release of a substance, presumably an analogue, from the damaged hypothalamo-neurohypophyseal system, which acts as an antagonist to normal AVP activity; after trans-sphenoidal operations diabetes insipidus seems to be caused by failure of AVP release.

Adolescent↗
PubMed1990

[Pituitary adenoma associated with neurofibromatosis: case report].

A case of pituitary adenoma associated with multiple neurinomas in the central nervous system was presented. A 52-year-old man was referred to us for surgical treatment of an intradural extramedullary cervical cord tumor. He had been operated on for a cauda equina tumor when he was 43 years old, and again for a glossopharyngeal neurinoma at 49 years of age. His brother expired in childhood, and had multiple subcutaneous nodules. The patient had been complaining of left leg pain, left shoulder pain, and hypesthesia of the right leg and foot. Examination showed 6th cervical nerve root sign. MRI revealed a well-circumscribed extramedullary tumor at the C5 level, and, in addition, incidentally showed an intra- and supra-sellar tumor which was isointensity on T1 weighted and high intensity on T2 weighted images. Myelography showed multiple extramedullary tumors in the lumbar region. Endocrinological study revealed an increased serum prolactin level (818.0ng/ml). The patient had neither café au lait spots nor subcutaneous nodules. A neurinoma of C6 root was totally removed and chromophobe pituitary adenoma was partially removed through a transsphenoidal approach. Neurofibromatosis is known to be associated with many kinds of tumors in the central nervous system. They are usually neurinomas, meningiomas or gliomas, and association of pituitary adenomas has been reported in only three cases, one of which being a prolactin secreting adenoma. Coexistence of multiple primary brain tumors has been also reported apart from phakomatosis. The most common combination is association of glioma and meningioma, and it is probably incidental coexistence due to their high frequency.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma, Chromophobe↗
PubMed1990

Rathke's cleft cyst: computed tomographic scan and magnetic resonance imaging.

Three patients with histologically proved Rathke's cleft cysts (RCCs) were evaluated with magnetic resonance imaging (MRI) and computed tomographic (CT) scan. Thirteen cases reported in the previous literature were also reviewed to evaluate the MRI features of RCCs and to compare them with CT features. The RCCs had various patterns of signal intensities on T 1-weighted and T 2-weighted MRI. The cysts were well-circumscribed and mainly in the sella turcica extending to the suprasellar cistern with minimal mass effect. Ten of sixteen cases had homogeneous cysts, and six had heterogeneous cysts. The CT scans showed the cysts as low or isodensity, well-demarcated lesions in the sella, that did not enhance with a few exceptions in which a thin ring enhancement was seen. MRI is superior to CT in the evaluation of the RCC, and is particularly useful in surgical planning, although MRI has a limitation on the specific, analytic description of the cyst contents.

Cysts↗
PubMed1990

Interface between the meningioma and the brain on magnetic resonance imaging.

Magnetic resonance imaging of 31 meningiomas in 29 patients was retrospectively reviewed and compared with pathologic specimens in 25 tumors to investigate how magnetic resonance imaging could delineate a tumor-brain interface. The thick, collagenous connective tissue, which was seen around four tumors, was shown as a low signal intensity rim on both a T1-weighted image and a T2-weighted image. A rim of low signal intensity on a T1-weighted image and high signal intensity on a T2-weighted image most likely represented cerebrospinal fluid space: this finding was seen around eight tumors. No distinct rim could be identified in five tumors. Of these five, two tumors grew invasively into the brain. Although mixed features predominated in meningiomas, magnetic resonance imaging could well delineate a tumor-brain relationship in most of the cases.

Adult↗
PubMed1990

Magnetic resonance imaging of large and giant intracranial aneurysms.

Twelve large or giant intracranial aneurysms were studied with magnetic resonance (MR) imaging, and the findings were compared with those from computed tomographic (CT) scanning. Characteristic MR features of such aneurysms are: round, extra-axial mass with hypointensity rim; signal void, paradoxical enhancement, or even-echo rephasing due to blood flow; and laminated, eccentric thrombus with increased signal intensity when fresh, perianeurysmal hemorrhage occurs in the acute or subacute stage after aneurysmal rupture. MR imaging, however, often fails to identify or characterize the area of calcification. For the diagnosis of large or giant intracranial aneurysms, MR imaging is apparently superior to CT scanning in differentiating aneurysms from tumors, delineating the blood flow and intraluminal thrombus, and detecting the exact size of the aneurysm. It may also provide useful information concerning the growth mechanisms of aneurysms with or without thrombus formation.

Adult↗
PubMed1989

Pituitary adenoma with multiple ciliated cysts: transitional cell tumor?

The case of a prolactin-secreting pituitary tumor with multiple cyst formation is described. Ultrastructurally, the cyst-lining cells were ciliated and closely resembled those of Rathke's cleft cyst but contained secretory granules, and no basal lamina formation was seen between the adenoma cells and the lining cells. Immunohistochemical study revealed that the adenoma cells consisted of both prolactin-secreting cells and growth hormone-secreting cells. The lining cells were immunoreactive with the antiserum to cytokeratin. No S-100 protein-positive cells were seen. The origin of this tumor is discussed.

Adult↗
PubMed1989

Indolent glioma: a cause of epilepsy.

We studied eight patients with indolent gliomas. In all eight cases, despite characteristic radiological features, there was a delay in diagnosis because of misinterpretation of the initial computed tomogram. These tumours are an important cause of epilepsy of childhood, and surgery may well alleviate the epilepsy and possibly achieve a long term 'cure'. Therefore it is important that a diagnosis is made early and the lesion completely excised.

Astrocytoma↗