Hideaki Masuzawa

Recurrence of convexity meningiomas: tumor cells in the arachnoid membrane

BACKGROUND It remains open to debate why totally removed benign meningiomas recur. Two recurrent cases forced us to reconsider something corresponding to their recurrence that we had overlooked during Simpson grade I surgery. METHODS This study is based on 24 recent and 9 earlier cases in which benign convexity meningiomas were totally removed by Simpsons grade I surgery. Tough or thick arachnoid membranes continuing to normal arachnoid membranes and contiguous to meningiomas but different from dura mater were encountered in 11 recent and at least 2 earlier cases. Such thick arachnoid membranes were left in place or only partially resected in two earlier cases but extensively resected in all recent cases. RESULTS Light microscopy showed clusters of meningioma cells not in the removed dura mater but in the thick arachnoid membranes of an earlier case and 10 out of the 11 recent cases. Six and twelve years after initial surgery, recurrence of the 2 earlier cases was confirmed at subsequent surgery or diagnosed by neuro-imaging. By contrast, neuro-imaging from 30 to 132 months after initial surgery showed no recurrence in the 10 recent cases. A follow-up study over 5 years showed a significant difference in recurrence between Simpsons grade I surgery with and without extensive removal of surrounding thick arachnoid membranes (Fishers exact test: p < 0.05). CONCLUSION This study emphasizes the possibility that thick arachnoid membranes contiguous to meningiomas and continuous to normal arachnoid membranes, involving clusters of tumor cells, may relate to meningioma recurrence.

Bilateral Chronic Subdural Hematomas without Communication between the Hematoma Cavities: Treatment with Unilateral Subdural-Peritoneal Shunt

&NA; Communication between bilateral subdural hematoma cavities was not demonstrated by metrizamide computed tomography subdurography in three patients with bilateral chronic subdural hematomas. Because unilateral subdural tapping yielded a slack fontanel without untoward neurological findings, patients were treated by the placement of unilateral subdural‐peritoneal shunts, resulting in resolution of the bilateral hematomas.

Capillary hemangioblastoma: histogenesis of stromal cells.

SummaryThe histogenesis of stromal cells in capillary hemangioblastoma has been the subject of debate. The light and electron microscopic studies of hemangioblastomas presented here showed pericytic and leiomyoblastic features in stromal cells. Cells cultured by the monolayer method showed similar features to those of the original tumors. Immunohistochemical studies for glial fibrillary acidic protein and factor VIII/von Willebrand factor indicated that stromal cells were antigenically distinct from astrocytes and endothelial cells. These findings suggest that stromal cells are closely related to pericytes and smooth muscle cells, and support Rhodins speculation that pericytes serve as a precursor to smooth muscle cells.

Saccular cerebral aneurysms in young adults

BACKGROUND The formation and rupture of cerebral aneurysms has been controversial. In order to clarify their nature, this study investigates the size and location of ruptured and unruptured aneurysms in young adults and the results of surgery. METHODS The subjects of this study are 35 patients with ruptured and two with unruptured aneurysms. They range in age from 20 to 39 years. The size and location of their aneurysms were determined by angiographic measure of their maximal inner diameters. Direct surgery was performed on 34 patients with ruptured aneurysms and on one with an unruptured aneurysm. RESULTS Ruptured aneurysms in young adults increase in number and size as they grow older. In young adults showing no atherosclerosis or hypertension, ruptured aneurysms occurred in locations and with a frequency found in patients with hypertension. In young adults, aneurysms in the internal carotid artery larger than 3.5 mm (Fishers exact test; p < 0.05) and the anterior communicating artery showed a tendency to rupture. The surgery produced excellent results in young adults with grade I to III by Hunt and Kosnik classification, but extremely poor results for those with grade IV resulting from vasospasm (Fishers exact test; p < 0.05). CONCLUSION It is possible that aneurysms found in young adults might in fact have been present from childhood and adolescence, increasing sufficiently in size to rupture in the forties and fifties. Accordingly, while aneurysm formation may be related to fragile arterial walls, aneurysm rupture may be the result of aging factors such as hypertension and atherosclerosis. Even in young adults, vasospasm had an impact on the outcome of surgery.

Pontine gliomas causing locked-in syndrome.

The terminal phase of pontine glioma is reportedly characterized by disturbance of consciousness. The authors retrospectively reviewed 8 children who died of pontine gliomas in their hospitals. The hospital records were analyzed specifically in regard to neurological status and terminal case. All children became mute and quadriplegic with cranial nerve palsies. The oldest child, 17 years in age, unquestionably showed the classical locked-in syndrome for the last 4 months. Six of the remaining 7 (average 5 years of age), while labeled as semicomatose, responded to calling by blinking and/or vertical eyeball movement. The authors consider that they were indeed awake in the locked-in state until very near death. This would raise a serious ethical problem of whether or not they should be intubated and kept ventilator-dependent at the time of respiratory failure, which often occurs.

Ultrastructure of concentric laminations in primary human brain tumors

SummaryUltrastructural concentric laminations have previously been thought to be specific to oligodendroglioma. However, these structures were also recognized in fibrillary astrocytomas, a mixed glioma and a glioblastoma. These laminations continued or closely related to attenuated processes or cytoplasm of astrocytic tumor cells. In addition, some lamellae contained glial filaments. It is considered that the concentric laminations are derived from attenuated astrocytic processes and have no relationship with myelin.

Mixed oligodendroglioma and astrocytoma: Fine structural and immunohistochemical studies of four cases

Four mixed oligodendrogliomas and astrocytomas were investigated by electron microscopy and immunohistochemistry (GFAP, NSE and MBP). GFAP-positive oligodendroglioma cells and their transitional cells to GFAP-negative oligodendroglioma cells were present, suggesting successive morphological changes of astrocytic tumor cells. NSE-positive cells, suggestive of residual neurons, also exhibited round nuclei and perinuclear halos. On electron microscopy, oligodendroglioma cells that showed glial filaments, vascular end-feet and zonulae adherentes were occasionally present. The tumor cells with or without astrocytic characteristics showed common features of cytoplasmic organelles. These findings suggest that most oligodendroglioma cells in mixed gliomas are of an astrocytic nature and that characteristic microscopic features of oligodendroglioma are of a common cellular form that can be taken by various types of cells under certain circumstances.

Astrocytic characteristics of oligodendroglioma: Fine structural and immunohistochemical studies of two cases

Two oligodendrogliomas were studied by light and electron microscopy. Additionally, an immunohistochemical study for glial fibrillary acidic protein (GFAP) was carried out. Some tumor cells exhibited glial filaments and perivascular end-feet, as on the one hand is characteristic of astrocytes, and glycogen granules and zonulae adherents which on the other hand are often seen in astrocytes but rarely in oligodendrocytes. Tumor cells with or without astrocytic characteristics showed the common fine structures and appeared to be on the same cell line. Our fine structural and immunohistochemical findings suggest that oligodendroglioma cells are of an astrocytic nature.

Secretory granules of pituitary adenomas: quantitative study of hormonal antigenicity

Abstract Ultrastructurally, the antigenicity of major pituitary hormones in secretory granules was quantitatively investigated in five growth hormone (GH)-secreting adenomas, five prolactin (PRL)-secreting adenomas and eight clinically non-functioning (CN-F) adenomas. Sparsely granulated cells with a few or several small secretory granules (60–100 nm) exhibiting little or only weak antigenicity of various biochemically unrelated hormones were commonly observed in CN-F adenomas and occasionally in GH- and PRL-secreting adenomas. GH- or PRL-secreting adenomas consisted of many densely granulated cells with medium-sized (200–250 nm) or large (over 250 nm) secretory granules and a few or several sparsely granulated cells with small secretory granules. The densely granulated cells showed intense GH or PRL antigenicity and slight to moderate antigenicity for other hormones in large secretory granules and little or only weak antigenicity for various hormones including GH or PRL in small secretory granules. Their secretory granules larger than 160 nm or 140 nm significantly exhibited intense GH or PRL antigenicity (Fisher’s exact test; P < 0.05 and < 0.01, respectively). Two CN-F adenomas showed sparsely and densely granulated cells as well as intermediate cells. The densely granulated cells closely resembled GH-secreting cells. The intermediate cells simultaneously included small and medium-sized or large secretory granules exhibiting little/slight and intense GH-antigenicity, respectively. This study indicates that sparsely granulated cells of different categories showing slight antigenicity for various hormones, antigenically share the same origin, and that their hormonality, single or multiple, may be selectively activated in the developmental course of secretory granules.

The multihormonal character of pituitary adenomas: Immuno-electron microscopic studies

This study investigates the multihormonal character of pituitary adenomas at the ultrastructural level. The growth hormone (GH)‐ and prolactin (PRL)‐secreting adenomas under study consisted of many moderately or densely granulated cells and a few sparsely or slightly granulated cells. The GH‐secreting adenomas showed well‐developed cytoplasmic organelles and many large (250 nm or more) or medium‐sized (200 nm) secretory granules, as well as a few small (70–150 nm) secretory granules. The PRL‐secreting hormones exhibited poorly or slightly developed cyto‐plasmic organelles and several small secretory granules. Morphologically and antigenically, these sparsely or slightly granulated cells were similar to those of clinically non‐functioning (CN‐F) adenomas, which appeared identical to cells expressing little or slight immunoreaction to pituitary hormones at the light microscopic level. As well as those of CN‐F adenomas, the small secretory granules of both densely and sparsely granulated cells expressed little or only slight antigenicity of various hormones. Con‐comitantly showing slight or moderate antigenicity of hormones biochemically unrelated to GH or PRL, the medium‐sized or large secretory granules larger than 140 or 160 nm significantly exhibited intense PRL or GH antigenicity, respectively (Fishers exact test; P < 0.05 or 0.01). Their GH or PRL antigenicity increased as they grew larger. Showing intermediate cells between sparsely and densely granulated cells, two CN‐F adenomas, however, appeared to develop into growth hormone‐secreting adenomas. This study led us to conclude that pituitary adenomas may originate from sparsely granulated cells with slight biochemically unrelated hormones, and that their hormonality may be selectively activated singly or multiply in the course of their development.