Masami Kamio

Neuroendoscopic anatomy and surgery in pineal region tumors

The therapeutic modalities for pineal region tumors in Western countries differ from those in far-eastern countries, that is, Japan and Korea, mainly because of the different patient populations. The majority of pineal region tumors in Japan and Korea are radio sensitive and/or chemosensitive, and adjuvant therapy rather than extensive surgery plays the main part in the treatment of these tumors. The authors have applied minimally-invasive preferential management in pineal region tumors in last 8 years. For the therapeutic regimen, if the tumor markers alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG) were not detected in serum and there was significant ventricular dilation visualized on neuroimages, neuroendoscopic surgery was first applied for tumor debulking with tissue diagnosis and gross morphological analysis of the tumor and the intraventricular structures, followed by third-ventriculostomy. In the results, our minimally-invasive preferential regimen clarified the precise indication for neuroendoscopic procedures, and the majority of our patients with dilated ventricles and no evidence of tumor markers were treated satisfactorily with effective neuroendoscopic procedures as the initial procedure. Then avoided unnecessary craniotomy and radiotherapy and promised excellent therapeutic outcomes. Neuroendoscopic procedures have a great advantage in the management of chemo- or radiosensitive tumors, such as germinoma, pineoblastoma, or primitive neuroectodermal tumor. The neuroendoscopic anatomy including the lateral and third ventricles with a pineal region tumor with or without tumor dissemination was described in detail, together with the neuroendoscopic surgical technique.

Single secretory granules contain both GH and prolactin in pituitary mixed type of adenoma

A mixed type of pituitary adenoma is described consisting of heavily and sparsely granulated cells. It produces GH and prolactin (PRL) and has been examined by immunocytochemistry. The superimposition immunocytochemical procedure reveals that single cells contain both GH and PRL. Furthermore, electron immunocytochemistry using adjacent sections reveals that single secretory granules contain both GH and PRL simultaneously.

Endoscopic transethmosphenoidal approach for pituitary tumors with image guidance

The advantages of endoscopic transethmosphenoidal surgery for pituitary tumors using a navigation system were reported. The surgical technique was as follows. First, sphenoidal sinuses were opened via the bilateral ethmoidal sinuses and the olfactory clefts. Then the septum of the sphenoidal sinuses was resected. Next, an endoscope was inserted via the left nasal cavity and fixed in place. The tumor was then removed via the right nasal cavity. Our approach for pituitary tumors provided sufficient working space and permitted the surgeon to carry out the procedure using both hands. In addition, use of the InstaTrak System made it possible to recognize the orientation of the surgical field in the sella turcica. Thus, the tumor could be resected more easily and safely. It is concluded that this approach will be particularly useful for patients with narrow nasal cavities or poor development of the paranasal sinuses.

Germ Cell Tumors of the Basal Ganglia and Thalamus

The clinicopathological findings in 6 patients with germ cell tumors originating in the basal ganglia and thalamus are presented. Clinical, biological and diagnostic features were somewhat different from germ cell tumors in the pineal region. Early and comprehensive treatment is recommended because of the possible presence of nongerminomatous germ cell components.

Immunohistochemical Analysis of 11-β-Hydroxysteroid Dehydrogenase Type 2 and Glucocorticoid Receptor in Subclinical Cushing’s Disease due to Pituitary Macroadenoma

Subclinical Cushing’s disease (SCD) is characterized by lack of clinically evident Cushingoid features, despite abnormal hypersecretion of ACTH. Nearly half the cases of SCD are due to macroadenomas, and in the majority of them, ACTH secretion is not inhibited even by high-dose dexamethasone. Impaired glucocorticoid (GC) action may be correlated with the proliferation and development of pituitary macroadenomas causing SCD. In this study, immunohistochemical analysis of the resected tumors were performed to evaluate the expression of 11β-hydroxysteroid dehydrogenase type 2 (11βHSD2) and glucocorticoid receptor (GR) in pituitary tissues obtained from two SCD (macroadenomas), eight Cushing’s disease (CD) (microadenomas), nine acromegaly, and nine normal pituitary (NP). Scattered 11βHSD2-immunopositive cells were detected in all NP tissues, but its immunoreactivity was totally absent in any tumorous tissues except two CD. Scattered GR-immunopositive cells were also detected and GR immunostaining was restricted to the cytosol in NP tissue. In contrast, GR-immunopositive cells were abundantly present and GR immunostaining was restricted to the nucleus in all the tumorous tissues. There were marked differences in both expression levels and localization between NP tissues and all the tumors. There may be a mechanism other than that via 11βHSD2 for causes of impaired negative feedback action by GC in SCD and CD, but results of our present study suggest that impaired GC action may be involved, at least in part, in tumorigenesis of SCD and CD.

Endoscopic Transnasal Approach to the Pituitary Lesions Using Navigation System (InstaTrakTM System)

Summary Endoscopic transnasal approach has become a procedure of choice for the surgical management of pituitary lesions. However, in conventional endoscopic transnasal surgery, the surgeon may become disorientated to the actual operating position. In our series, 47 patients have undergone an endoscopic transnasal approach to the pituitary with the use of the navigation system called InstaTrakTM for real-time imaging. This image guidance system proved valuable for anatomical localization during pituitary surgery. We have reduced the average surgical time, and improved patient outcome. As a consequence, complications during surgery should decrease and safety should increase. Intra-operative image guidance is expected to have major advantageous effects on pituitary surgery by allowing the surgeon to remove lesions more efficiently. As this system is improved technically and surgeons become more proficient in their use, there should be better postoperative outcomes.

A new surface modification technique of platinum coils by ion implantation and protein coating: Use in intravascular treatment of brain aneurysms

Abstract Ion implantation and protein-coatings were utilized to alter the surface properties (thrombogenicity, endothelial cellular migration and adhesion) of microcoils (GDCs) for intravascular treatment of brain aneurysms. These modified coils were compared with standard GDCs in the treatment of experimental swine aneurysms. Improved cellular adhesion and proliferation was observed with use of the modified coils. The results of this preliminary investigation indicate that future application of this technology may provide early wound healing at the necks of embolized wide-necked brain aneurysms.

Ion Implantation Modifies the Surface of GDCs. An Experimental Study in Swine Aneurysms.

Ion implantation and protein-coatings were utilized to alter the surface properties (endothelial cellular adhesion) and enhance the thrombogenicity of Guglielmi detachable coils (GDCs) for endovascular treatment of cerebral aneurysms. These modified GDCs were compared with standard GDCs in the treatment of experimental swine aneurysms. Standard GDCs and ion-implanted protein coated GDCs were used to treat 32 aneurysms in 16 swine. GDCs were coated with either proteins, collagen (n = 5), vitronectin (n = 4), fibrinogen (Fn = 3), laminin (n = 2), or fibronectin (n = 2) and underwent Ne+ or He+ implantation with a fluence of 1 × 1014– 1015 ions/cm2 at an energy of 150 keV. Bilateral experimental swine aneurysms were embolized with standard GDCs (n = 16) on one side and with ion-implanted protein-coated GDCs (n = 16; total) on the other side. The necks of aneurysms were evaluated macroscopically and histopathologically at autopsy using day 14 post-treatment specimens. Greater fibrous coverage of the necks of aneurysms were observed in the ion-implanted coil group. The results of this experimental study indicate that Ion implantation combined with protein coating of GDCs improved cellular adhesion and proliferation. Future application of this technology may provide early wound healing at the necks of embolized wide-necked cerebral aneurysms.