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Background:  Pineal apoplexy, alternatively referred to as pineal hemorrhage or pineal gland hemorrhagic stroke, is an infrequent pathologic condition characterized by bleeding within the pineal gland. In this review, we encompass the primary factors contributing to this uncommon ailment., Methods:  The retrieval of pertinent research, including patients with pineal apoplexy, was conducted through PubMed, Google Scholar, and Scopus databases. This study exclusively incorporated comprehensive articles written in the English language. The search encompassed the MeSH terms "pineal apoplexy" and "pineal hemorrhage.", Results:  A total of 41 articles were identified, encompassing a collective sample size of 57 patients. The median age of the patients in the study was 30 years, with a range spanning from 1 to 73 years. There were 27 males, representing 47.4% of the participants. The study identified the most often reported symptoms as headache (49; 86%), nausea/vomiting (19; 33.3%), and Parinaud's syndrome (16; 28.1%). The treatment options encompass several approaches, including open resection, shunting, ventriculostomy, endoscopic aspiration, and conservative care. In the conducted study, a notable number of patients, amounting to 45 cases (78.9%), indicated an amelioration of their symptoms upon their discharge., Conclusion:  Data from a cohort of 57 cases provide insights into symptoms, lesions, treatments, and outcomes. Management approaches range from conservative measures to surgical interventions, with prognosis hinged on timely intervention. This investigation serves as a valuable resource for clinicians and researchers, underscoring the need for early diagnosis before permanent neurologic dysfunction happens and tailored treatments for optimal outcomes in pineal apoplexy cases., Competing Interests: None declared., (Thieme. All rights reserved.)

Objective: Vascular lesions of the pineal region comprise aneurysms of the pineal region, arteriovenous malformations, cavernous malformations, and vein of Galen malformations. In the present report, we have offered an extensive review of each vascular pineal region lesion., Methods: We performed an extensive literature review, focusing on the current therapeutic options available for the different vascular lesions of the pineal region., Results: Vascular lesions of the pineal region are rare. Microneurosurgery remains a valid treatment of cavernomas, arteriovenous malformations, and aneurysms. Endovascular treatments seem to be the first option for the vein of Galen malformations, followed by microneurosurgery. Radiosurgery seems beneficial for small-size arteriovenous malformations. Complex and large vascular lesions will require a combination of multiple treatments., Conclusions: Vascular lesions of the pineal region are complex, uncommon diseases. Thus, definitive therapeutic modalities for these lesions require further research., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: The anatomy of the veins in the pineal region is one of the most complex areas in the brain because all major deep cerebral veins converge there: the internal cerebral veins (ICVs), the great cerebral vein of Galen (GV), the basal veins (BVs), and the internal occipital veins (IOVs). The aim of this study was to comprehensively describe the anatomy of the veins in the pineal region using computed tomography angiography., Methods: Head computed tomography angiography scans of 250 adult Polish patients were evaluated. We assessed the location of the junction of 2 ICVs and the presence of a narrowing of the GV and arachnoid granulation at the GV-straight sinus junction. We evaluated the presence, appearance, and termination of the BV, and the presence and termination of the IOV., Results: The study showed that 2 ICVs usually converged posterior to the splenium of the corpus callosum (62.4%). Narrowing of the BV was observed in 51.2% of patients, and the arachnoid granulation was found in 25.2%. The 3 segments of the BV were well visualized in 66% of the studied hemispheres. The BV flowed into the GV in 34.8% of the hemispheres. The IOV was present in 90.2% of the hemispheres and terminated medially in 84.5%., Conclusions: Because an injury to major deep cerebral veins may result in severe postoperative neurologic deficits, it is essential for neurosurgeons to be familiar with both normal and variant patterns of veins in the pineal region., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Surgical experience in pineal surgery is largely confined to a few experienced surgeons and may be lost when they stop their practice. The objective of this study is to systematically preserve and analyze valuable practical knowledge of pineal region surgical venous anatomy. A survey was constructed to obtain experienced surgeons' perception of estimated risks and individual experience following occlusion of veins during pineal surgery. Data were qualitative and analyzed with a mixed methods approach. Of the 126 invited neurosurgeons, 40 submitted completed questionnaires. General agreement existed of which veins were associated with high and low risks following occlusion. The risk of death was estimated to be high with sacrifice of the vein of Galen (83%), both internal cerebral veins (69%) and the basal veins (58%). The risk of death was estimated to be lower with the sacrifice of both superior vermian veins (13%) and one internal occipital vein (10%). Importantly, a sub-group of experienced surgeons reported substantial risk of death and consequences with the sacrifice of cerebellar bridging veins (8-13%). Our findings provide a coherent picture of surgical risk with venous sacrifice, which can inform the surgical community of systematically gathered views from aggregated surgeries of a very large cohort of patients. Extensive presurgical radiological workup and anatomical studies seemed to correlate more cautious risk estimations. Our findings increase available knowledge of risks of venous complications.

Background: Vascular pineal malformations are rare and technically demanding lesions. Because the locations of these lesions, endovascular techniques and radiosurgery have been increasingly used in the recent decades to accomplish safe occlusion. Nevertheless, microsurgical treatment may be required sometimes., Methods: We present a retrospective review of the vascular pineal malformations operated by the senior author. Moreover, we report illustrative cases for the various types of vascular lesions with a careful analysis of the different microsurgical stages., Results: Eighteen patients with pineal vascular lesions were operated on between 1980 and 2015: 6 patients had vein of Galen malformations, 5 plexiform arteriovenous malformations, 6 cavernous malformations, and 1 patient had a ruptured medial posterior choroidal artery aneurysm. A complete resection and occlusion was possible in all vascular malformations., Conclusions: The pineal region is an infrequent but challenging location for vascular lesions. A careful and stepwise operative strategy for the different types of vascular lesion is paramount to accomplish an effective and safe microsurgical treatment when other alternatives fail or are not available., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: In recent decades endoscopic techniques have been increasingly used in neurosurgery as they may offer a valuable close-up view of the working area through a minimally invasive surgical corridor. Herein, we present an inexpensive and efficient endoscopic surgical model using a borescope, which was used for a "modified pure endoscopic approach" to the pineal region., Methods: A borescope video camera was connected to a 16-inch personal computer monitor. A standard midline suboccipital craniotomy was performed on 2 cadaveric heads in the Concorde position. Then, a "borescopic" supracerebellar infratentorial approach was executed, thus reaching the pineal region, which was exposed through an extensive arachnoid dissection., Results: Using the previously described model, we were able to provide excellent exposure of the main neurovascular structures of the pineal region, as shown by the intraoperative videos. In 1 specimen we identified an incidental pineal cyst that was meticulously dissected and removed., Conclusions: Our proposed "borescopic" surgical model may represent an inexpensive and efficient alternative to conventional endoscopic techniques and could be used for training purposes, as well as even for clinical procedures, after a proper validation, particularly in economically challenging environments., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Gap junctions between cells in the pineal gland have been described ultrastructurally, but their connexin constituents have not been fully characterized. We used immunofluorescence in combination with markers of pineal cells to document the cellular localization of connexin43 (Cx43). Immunofluorescence labelling of Cx43 with several different antibodies was widely distributed throughout the pineal, whereas another connexin examined, connexin26, was not found in pineal but only in surrounding leptomeninges. Labelling apparently associated with plasma membranes was visualized either as fine Cx43-puncta (1-2 μm) or as unusually large pools of Cx43 ranging up to 4-7 μm in diameter or length. These puncta and pools were highly concentrated in perivascular spaces, where they were associated with numerous cells devoid of labelling for markers of pinealocytes (e.g. tryptophan hydroxylase and serotonin), and where they were minimally associated with blood vessels and lacked association with resident macrophages. Astrocytes labelled for glial fibrillary acidic protein were largely restricted to the anterior pole of the pineal gland, where they displayed only fine and sparse Cx43-puncta along their processes. Labelling for Cx43 was localized largely though not exclusively to the somata and long processes of a subpopulation of perivascular interstitial cells that were immunopositive for calbindin-D28K. These cells were often located among dense bundles or termination areas of sympathetic fibres labelled for tyrosine hydroxylase or serotonin. The results indicate that interstitial cells form abundant gap junctions composed of Cx43, and suggest that gap junction-mediated intracellular communication by these cells supports the activities of pinealocytes., (© 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)

Introduction: The pineal region is situated in the posterior part of the incisural space. This region includes the pineal body inside the quadrigeminal arachnoidal cistern. This article reviews the anatomic features of this region, with particular emphasis on those aspects of importance for surgical access to the pineal region., Material & Methods: Five cadaver heads fixed in 10% formalin and injected with colored latex were used for anatomic dissection (five other specimens were also prepared and dissected to illustrate the articles on surgical techniques and approaches presented elsewhere in this issue)., Results: The pineal body is surrounded by several important structures such as: posterior part of the third ventricle, tectum, the complex of the great cerebral vein of Galen, pulvinar nuclei of the thalamus and splenium of corpus callosum., Conclusion: The surgical approach of the pineal body, whatever the route or the technique used (microsurgical, endoscopic or stereotactic), creates a great challenge for the neurosurgeons due to its location in the deep part of the brain and its close relationships with complex surrounded vascular structures., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Historically, the direct release of pineal melatonin into the capillary bed within the gland has been accepted as the primary route of secretion. Herein, we propose that the major route of melatonin delivery to the brain is after its direct release into the cerebrospinal fluid (CSF) of the third ventricle (3V). Melatonin concentrations in the CSF are not only much higher than in the blood, also, there is a rapid nocturnal rise at darkness onset and precipitous decline of melatonin levels at the time of lights on. Because melatonin is a potent free radical scavenger and antioxidant, we surmise that the elevated CSF levels are necessary to combat the massive free radical damage that the brain would normally endure because of its high utilization of oxygen, the parent molecule of many toxic oxygen metabolites, i.e., free radicals. Additionally, the precise rhythm of CSF melatonin provides the master circadian clock, the suprachiasmatic nucleus, with highly accurate chronobiotic information regarding the duration of the dark period. We predict that the discharge of melatonin directly into the 3V is aided by a number of epithalamic structures that have heretofore been overlooked; these include interpinealocyte canaliculi and evaginations of the posterodorsal 3V that directly abut the pineal. Moreover, the presence of tanycytes in the pineal recess and/or a discontinuous ependymal lining in the pineal recess allows melatonin ready access to the CSF. From the ventricles melatonin enters the brain by diffusion and by transport through tanycytes. Melatonin-rich CSF also circulates through the aqueduct and eventually into the subarachnoid space. From the subarachnoid space surrounding the brain, melatonin penetrates into the deepest portions of the neural tissue via the Virchow-Robin perivascular spaces from where it diffuses into the neural parenchyma. Because of the high level of pineal-derived melatonin in the CSF, all portions of the brain are better shielded from oxidative stress resulting from toxic oxygen derivatives.

Intratumor hemorrhage is a poor prognostic factor in pineal choriocarcinoma (PCCC). The aim of this study was to understand the relationship of tumor cells to the blood vessels to gain insights into the formation of intratumor hemorrhage in PCCC. The clinical data indicated that total tumor removal by surgical procedures followed immediately by radiotherapy and chemotherapy improved the prognosis in PCCC. The PCCC tissues removed from the patients were examined by histology and immunohistochemistry. Hematoxylin and eosin staining showed that the tumor stroma mainly consists of hemorrhagic tissues with tumor cells scattered inside. The pattern of distribution suggests that the tumor cells were possibly flushed and compressed by the bleeding. The tumor cells tended to form sinusoids that lacked CD34, but laminin expression provided evidence of vasculogenic mimicry. Interestingly, CD34-positive blood vessels were found connected to these sinusoids, suggesting that blood may flow from the tumor vasculature to the sinusoids. This may subsequently cause the enlargement of the sinusoids, blood clotting, the widening of the blood lakes, and eventually extensive hemorrhagic necrosis. Our study identified the key features of the PCCC vasculature. The findings add to the previous understanding of the formation of vascular channels, blood lakes, and extensive hemorrhagic necrosis. The intimate connections between the tumor-formed sinusoids and the blood vessels might be a major cause of severe hemorrhage in PCCC. The new information may be useful for the development of treatment strategies for managing PCCC.

Purpose: The arterial vascularization of the pineal gland (PG) remains a debatable subject. This study aims to provide detailed information about the arterial vascularization of the PG., Methods: Thirty adult human brains were obtained from routine autopsies. Cerebral arteries were separately cannulated and injected with colored latex. The dissections were carried out using a surgical microscope. The diameters of the branches supplying the PG at their origin and vascularization areas of the branches of the arteries were investigated., Results: The main artery of the PG was the lateral pineal artery, and it originated from the posterior circulation. The other arteries included the medial pineal artery from the posterior circulation and the rostral pineal artery mainly from the anterior circulation. Posteromedial choroidal artery was an important artery that branched to the PG. The arterial supply to the PG was studied comprehensively considering the debate and inadequacy of previously published studies on this issue available in the literature., Conclusions: This anatomical knowledge may be helpful for surgical treatment of pathologies of the PG, especially in children who develop more pathology in this region than adults.

Pineal cysts are a common incidental finding in imaging studies, and the majority of such cysts are asymptomatic. However, hemorrhaging pineal cysts, which are considered to be rare, are often associated with severe symptoms. We herein describe the case of a 58-year-old patient with the novel manifestation of a bleeding pineal cyst, who had a benign outcome without any surgical treatment. Although the clinical manifestations resembled those of bacterial meningitis, magnetic resonance images suggested chemical meningitis caused by an intracystic hemorrhage and rupture of the pineal cyst.

Magnetic resonance imaging (MRI) at 7.0 Tesla (7T) can show many details of anatomical structures with unprecedented resolution and contrast. In this report, we describe for the first time the unexpected wide variation in pineal gland structure, as visualized by MR images obtained with 7T in a group of healthy young volunteers. A total of 34 volunteers (22 men and 12 women) were enrolled in the study. Their 7T MR images revealed such wide variations in pineal gland shape that it led us to attempt to classify the patterns seen in these pineal glands. Indeed, they were successfully correlated with a previous human cadaver study of venous structures by Tamaki et al., who classified the venous structures of the pineal gland into three categories. This is the first human in vivo pineal vein imaging study using 7T MRI. Pineal venous imaging may permit the early diagnosis of a pineal tumor., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

Object: The purpose of this study was to identify the anatomy of pineal region venous complex using neuronavigation software when distorted by the presence of a space-occupying lesion and to describe the anatomical relationship between lesion and veins. Moreover we discuss its influence on the choice of the surgical strategy., Methods: Of the 33 patients treated at our Institute for pineal region tumors between 2003 and 2008 we used the neuronavigation software to depict the venous system of the pineal region in 14 patients. We focused on depiction of the basal vein of Rosenthal (BV), the internal cerebral vein (ICV) and the vein of Galen: connection patterns between the veins and the type of anatomical distortion caused by the lesion were investigated and classified., Results: Using the neuronavigation software for three-dimensional (3D) reconstruction of MRI images the ICV was clearly depicted in all patients on both sides (100%). Last segment of the BV was identified in 25 sides on a total of 28 (89.3%) and absent in 3 of the 28 sides (10.7%). Studying the distortion effect of the tumor on the galenic venous system, three directions of displacement were observed: craniocaudal, anteroposterior and lateral. Seven patients presented a cranial dislocation, 5 patients caudal dislocation and there was no craniocaudal shift in 2 patients. Considering the anteroposterior displacement: 3 subjects showed an anterior shift of the veins, 5 subjects posterior shift and no anterioposterior shift was present in 6 patients. Only 2 of the 14 patients presented lateral displacement of the veins. The principal approaches used in this series were: supracerebellar infratentorial and interhemispheric parieto-occipital. The craniocaudal displacement of the pineal veins seems to be the most important for the choice of the approach., Conclusion: The galenic venous system has a central role in the surgery pineal region tumors. Our study demonstrates that the architecture of the pineal veins and their anatomical relationship with the lesion can be depicted with great accuracy by using 3D neuronavigation software in order to facilitate surgical planning and intraoperative orientation., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Although the water channel protein aquaporin-1 (AQP1) is widely observed outside the rat brain in continuous, but not fenestrated, vascular endothelia, it has not previously been observed in any endothelia within the normal rat brain and only to a limited extent in the human brain. In this immunohistochemical study of rat brain, AQP1 has also been found in microvessel endothelia, probably of the fenestrated type, in all circumventricular organs (except the subcommissural organ and the vascular organ of the lamina terminalis): in the median eminence, pineal, subfornical organ, area postrema and choroid plexus. The majority of microvessels in the median eminence, pineal and choroid plexus, known to be exclusively fenestrated, are shown to be AQP1-immunoreactive. In the subfornical organ and area postrema in which many, but not all, microvessels are fenestrated, not all microvessels are AQP1-immunoreactive. In the AQP1-immunoreactive microvessels, the AQP1 probably facilitates water movement between blood and interstitium as one component of the normal fluxes that occur in these specialised sensory and secretory areas. AQP1-immunoreactive endothelia have also been seen in a small population of blood vessels in the cerebral parenchyma outside the circumventricular organs, similar to other observations in human brain. The proposed development of AQP1 modulators to treat various brain pathologies in which AQP1 plays a deleterious role will necessitate further work to determine the effect of such modulators on the normal function of the circumventricular organs.

The pineal gland is an evagination of the brain tissue, a circumventricular neuroendocrine organ. Our immunohistochemical study investigates basal lamina components (laminin, agrin, perlecan, fibronectin), their receptor, the dystrophin-dystroglycan complex (beta-dystroglycan, dystrophin utrophin), aquaporins (-4,-9) and cellular markers (S100, neurofilament, GFAP, glutamine synthetase) in the adult rat corpus pineale. The aim was to compare the immunohistochemical features of the cerebral and pineal vessels and their environment, and to compare their features in the distal and proximal subdivisions of the so-called 'superficial pineal gland'. In contrast to the cerebral vessels, pineal vessels proved to be immunonegative to alpha1-dystrobrevin, but immunoreactive to laminin. An inner, dense, and an outer, loose layer of laminin as two basal laminae were present. The gap between them contained agrin and perlecan. Basal lamina components enmeshed the pinealocytes, too. Components of dystrophin-dystroglycan complex were also distributed along the vessels. Dystrophin, utrophin and agrin gave a 'patchy' distribution rather than a continuous one. The vessels were interconnected by wing-like structures, composed of basal lamina-components: a delicate network forming nests for cells. Cells immunostained with glutamine synthetase, S100-protein or neurofilament protein contacted the vessels, as well as GFAP- or aquaporin-immunostained astrocytes. Within the body a smaller, proximal, GFAP-and aquaporin-containing subdivision, and a larger, distal, GFAP-and aquaporin-free subdivision could be distinguished. The vascular localization of agrin and utrophin, as well as dystrophin, delineated vessels unequally, preferring the proximal or distal end of the body, respectively.

Objective: The purpose of this study was to delineate the anatomy of the precentral cerebellar vein, superior vermian vein, and internal occipital vein using reconstructions of computed tomographic and magnetic resonance imaging scans with navigation software. These data were compared with previous anatomic and angiographic findings to show the resolution and accuracy of the system., Methods: We retrospectively reviewed 100 patients with intracranial pathologies (50 computed tomographic scans with contrast and 50 magnetic resonance imaging scans with gadolinium) using a neuronavigation workstation for 3-dimensional reconstruction. Particular attention was paid to depiction of the precentral cerebellar vein, superior vermian vein, and internal occipital vein. The data were reviewed and analyzed., Results: The precentral cerebellar vein, superior vermian vein, and its tributary, the supraculminate vein, were depicted in 52 (52%) patients. The internal occipital vein was delineated on 99 (49.5%) sides and joined the basal vein and vein of Galen in 39 (39.4%) and 60 (60.6%) hemispheres, respectively. Comparing these results with previous angiographic studies, the ability of the neuronavigation system for depicting these vessels is similar to that of digital subtraction angiography., Conclusion: This study illustrates the possibility of depicting the small vessels draining into the pineal region venous complex using 3-dimensional neuronavigation with an accuracy comparable to that of digital subtraction angiography. This tool provides important information for both surgical planning and intraoperative orientation.

Introduction: Although the association between headaches and pineal gland cysts has been suggested on a number of occasions, no precise evidence of exactly what this relation involves has been produced to date. It is known, however, that a cyst in the pineal gland can bring on or worsen headaches, especially if it is large or there has been bleeding, due to obstructive compromise in the third ventricle and the resulting hydrocephalus that is produced., Case Report: A 15 years-old male who had suffered from migraine from the age of 6 years and who suddenly experienced a worsening of his headaches, both as regards their frequency and their intensity, over the previous days; no known precipitating factor appeared to be involved. Magnetic resonance imaging of the brain revealed the presence of a giant cyst in the pineal gland, with a notable amount of blood inside it, which was producing an obstructive hydrocephalus. The decision was made to resort to surgical treatment, with resection of the cyst and placement of a shunt valve. As a result the patient's headaches improved greatly and this improvement continued throughout a six-month follow-up., Conclusions: Worsening of a headache, in this case migraine, for no apparent cause must make us consider secondary processes, although they may be as rare as the one described here.

The circumventricular organs are small sized structures lining the cavity of the third ventricle (neurohypophysis, vascular organ of the lamina terminalis, subfornical organ, pineal gland and subcommissural organ) and of the fourth ventricle (area postrema). Their particular location in relation to the ventricular cavities is to be noted: the subfornical organ, the subcommissural organ and the area postrema are situated at the confluence between ventricles while the neurohypophysis, the vascular organ of the lamina terminalis and the pineal gland line ventricular recesses. The main object of this work is to study the specific characteristics of the vascular architecture of these organs: their capillaries have a wall devoid of blood-brain barrier, as opposed to central capillaries. This particular arrangement allows direct exchange between the blood and the nervous tissue of these organs. This work is based on a unique set of histological preparations from 12 species of mammals and 5 species of birds, and is taking the form of an atlas.

Object: The purpose of this study was to determine the ability of software-assisted 3D reconstruction performed using a neuronavigation system to delineate the anatomy and variation patterns of the pineal region venous complex, and then to compare these data with previous anatomical findings., Methods: The authors retrospectively reviewed the neuroimages obtained in 100 patients with intracranial lesions (50 computed tomography [CT] scans obtained with contrast agents and 50 magnetic resonance [MR] images obtained with gadolinium) by using a neuronavigation workstation for 3D reconstruction. Particular attention was given to the internal cerebral vein, basal vein (BV), and the vein of Galen. The various connection patterns between the major vessels were classified and statistically analyzed., Conclusions: The venous system of the pineal region shows a wide range of sex-related variations. In the female patient the absence of a BV (Type 0) is significantly more frequent than in the male. In this study the authors illustrate the ability to depict the venous drainage patterns in the pineal region for all cases studied by using 3D neuronavigation software without the need for additional examinations. This simple tool provides important information for surgical planning and may be of significant help intraoperatively.

Pineal hemorrhage only occurs in rare cases, and this known to have several different causes such as germ cell tumors, pineal cysts and vascular malformations, including the cavernous malformations. Pineal cavernous malformations are extremely rare: to date only fifteen cases have been reported worldwide. Although the diagnosis of pineal cavernous malformation is not easy because of the extreme rareness of this condition, the presence of this lesion can be suspected based on its typical radiological findings. Case 1. A 42-year- old man presented with a limitation in his upward gazing. Radiologic examinations showed acute hemorrhage in the pineal region. He underwent ventriculo-peritoneal (VP) shunting but the patient's condition deteriorated after the shunting surgery. We operated and totally removed the tumor and the hemorrhages via an occipital-transtentorial approach. Case 2. A 37-year-old man presented with diplopia. Radiologic examinations showed acute hemorrhage in the third ventricle. He underwent VP shunting, and after this procedure the diplopia was aggravated. We operated and totally removed the tumor and the hemorrhages via an occipital-transtentorial approach. If there is no doubt about the pineal cavernous malformation on MR imaging, we strongly recommend early surgical intervention without performing a risky biopsy. In this study, we describe our experiences for the diagnosis of cavernous malformations in the pineal region with special emphasis on the radiological aspects and the clinical course of this disease.

Objective: This study aims at evaluating the adequacy of digital subtraction angiography and magnetic resonance venography in imaging of the galenic venous system for surgical planning of approaches to the pineal region. Anatomical dissections were carried out in 10 cadavers of several age groups and these were compared to imaging findings in 10 living subjects., Methods: The presence or absence of 10 predetermined veins or vein groupings belonging to the galenic venous system were prospectively analyzed in 10 cadaver dissections and imaging findings of 10 age matched human subjects. The studied vessels were the vein of galen, the internal cerebral veins, both basal vein of Rosenthals, internal occipital vein, occipitotemporal veins, precentral cerebellar veins, tectal veins, pineal veins, superior vermian veins (including superior cerebellar veins (SCVs)) and posterior pericallosal veins. Each of the subjects had both digital subtraction angiography and magnetic resonance venography studies performed. Diagnostic digital subtraction angiography was performed using the transfemoral route and the venous phase was used for the study. Magnetic resonance venography was performed in 1.5 T MRI equipment using the 2D-TOF sequence. All studies were reported to be normal., Results: There was wide variation in the anatomy of the galenic venous system. There were interpersonal, intrapersonal and age related variations. Both the digital subtraction angiography and the magnetic resonance venography were efficient at demonstrating large veins. However, smaller veins were less readily demonstrated in either study. The general sensitivities of the digital subtraction angiography and the magnetic resonance venography for the galenic venous system were 45.5% and 32.5%, respectively. Surgically important veins were missed in most studies., Conclusions: Anatomically, the galenic venous system is highly variable. This variability is caused by interpersonal, intrapersonal and age related differences and causes each individual galenic venous system to be unique. Therefore, modern neurosurgical procedures require anatomical information on individual differences. Current radiological methods of digital subtraction angiography and magnetic resonance venography fail short of providing the necessary information. New and more sophisticated MRI technology may fulfill this need.

In earlier works we have found that in the mammalian pineal organ, a part of autonomic nerves--generally thought to mediate light information from the retina--form vasomotor endings on smooth muscle cells of vessels. We supposed that they serve the vascular support for circadian and circannual periodic changes in the metabolic activity of the pineal tissue. In the present work, we investigated whether peripheral nerves present in the photoreceptive pineal organs of submammalians form similar terminals on microvessels. In the cyclostome, fish, amphibian, reptile and bird species investigated, autonomic nerves accompany vessels entering the arachnoidal capsule and interfollicular meningeal septa of the pineal organ. The autonomic nerves do not enter the pineal tissue proper but remain in the perivasal meningeal septa isolated by basal lamina. They are composed of unmyelinated and myelinated fibers and form terminals around arterioles, veins and capillaries. The terminals contain synaptic and granular vesicles. Comparing various vertebrates, more perivasal terminals were found in reptiles and birds than in the cyclostome, fish and amphibian pineal organs. Earlier, autonomic nerves of the pineal organs were predominantly investigated in connection with the innervation of pineal tissue. The perivasal terminals found in various submammalians show that a part of the pineal autonomic fibers are vasomotoric in nature, but the vasosensor function of some fibers cannot be excluded. We suppose that the vasomotor regulation of the pineal microvessels in the photosensory submamalian pineal--like in mammals--may serve the vascular support for circadian and circannual periodic changes in the metabolic activity of the pineal tissue. The higher number of perivasal terminals in reptiles and birds may correspond to the higher metabolic activity of the tissues in more differentiated species.

Objective: The veins draining the posterior wall of the third ventricle and its adjacent structures and the posterior part of the midbrain have been the most neglected of the intracranial vascular structures in both the anatomic and neurosurgical literature. During our dissections of the pineal region and the quadrigeminal cistern, we did not always encounter topographic anatomy as described in previous articles. The purpose of this study is to describe the topographic anatomy and normal variations of the specific veins that drain the collicular plate and the pineal body and their adjacent structures with a view to better defining neurosurgical approaches to the pineal region., Methods: The deep cerebral veins draining the pineal body, the collicular plate, and their surrounding neural structures were examined on both sides of 25 adult cadaveric brains. In all specimens, the carotid and vertebral arteries and the jugular veins were perfused with red or blue silicone, respectively, to facilitate dissection under x3 to x40 magnification., Results: The venous plexus on the dorsal aspect of the collicular plate drains via collicular veins according to three different patterns. These types of drainage are closely related to the existence or absence of the basal vein on one or both sides., Conclusion: The veins draining the superior and inferior aspects of the pineal body form a superior and an inferior pineal vein that usually drain into the internal or great cerebral vein.

Arterial vascularisation of the ovine pineal gland was investigated by latex injection preparations of the common carotid artery in 20 adult Akkaraman sheep brains under stereo light microscope. It was observed that the arterial supply comes exclusively from branches of the caudal cerebral artery. The pineal gland was found to contain a rich vascular network. This network also received a few branches from the caudal choroid rami.

Object: The deep cerebral veins may pose a major obstacle in operative approaches to deep-seated lesions, especially in the pineal region where multiple veins converge on the great cerebral vein of Galen. Because undesirable sequelae may occur from such surgery, the number of veins and branches to be sacrificed during these approaches should kept to a minimum. The purpose of this study was to examine venous drainage into the vein of Galen with a view to surgical approaches. If a vein hampering surgical access must be sacrificed, it can therefore be selected according to the smallest draining territory., Methods: The deep cerebral veins and their surrounding neural structures were examined in 50 cerebral hemispheres from 25 adult cadavers in which the arteries and veins had been perfused with red and blue silicone, respectively. Special consideration was given to the size and location of drainage of the vein of Galen and its tributaries., Conclusions: When a surgeon approaches the pineal region, several veins may hamper the access route. From posterior to anterior, these include the following: the superior vermian and the precentral or superior cerebellar veins, which drain into the posteroinferior aspect of the vein of Galen; and the tectal and pineal veins, which drain into its anterosuperior aspect. The internal occipital vein is the main vessel draining into the lateral aspect of the vein of Galen. It may be joined by the posterior pericallosal vein, and in that case has an extensive territory. To avoid intraoperative venous infarction, it is important to use angiography to determine the venous organization before surgery and to estimate the permeability and size of the branches of the deep venous system.

This study aimed at revealing arterial vascularization of the pineal gland of the Zavot-bred foetus. Twenty foetuses, regardless of their sex, at the age of 2-7 months were used. Coloured-latex was injected by way of both the right and left common carotid arteries. Then, dissection was performed and vessels nourishing the pineal gland were documented. The pineal gland is vascularized by a number of 2-5 central rami. A small vessel arising from each of the central rami in two foetuses (10%) was shown anastomosing with a branch of the cranial cerebral artery, which advances in cranio-caudal direction in the callosal groove. Hence, anastomoses were observed between several sub-branches of each caudal cerebral and cranial cerebellar arteries.

Objective: Direct surgical approaches to the posterior incisural space, including the pineal region, remain as challenges for neurosurgeons. The purposes of this study were 1) to compare the surgical views in the various posterior approaches to the posterior incisural space and 2) to propose a new approach, which is a modification of the occipital transtentorial approach., Methods: Ten adult cadaveric specimens (20 sides) were studied, using x3 to x40 magnification, after perfusion of the arteries and veins with colored silicone. Intraoperative views in the posterior approaches to lesions were examined in stepwise dissections. In addition, the efficacy of the occipital bi-transtentorial/falcine approach was studied., Results: The posterior incisural space has a roof, a floor, and anterior and lateral walls and extends backward to the level of the tentorial apex. The operative views defined by each approach differ in the extent to which they allow observation of the anatomic structures in the posterior incisural space. The occipital bi-transtentorial/falcine approach permits better observation of the contralateral half of the quadrigeminal cistern., Conclusion: Precise surgical anatomic knowledge of each approach is required for the treatment of lesions in the posterior incisural space, because the operative fields obtained with different approaches differ significantly. The occipital bi-transtentorial/falcine approach provides greater contralateral exposure of the posterior incisural space than does the occipital transtentorial approach.

Objectives: The content of C-Fos protein was tested in rat pinealocytes in the norm and stress and in case of intranasal administration of Epitalon (Ala-Glu-Asp-Gly), which regulated pineal secretion processes, presumably, via protooncogenes., Setting: Intact and osmotic-stress-exposed rats were used for the immunohistochemical detection of C-Fos protein. All animals were intranasally administered with Epitalon, the last infusion made in two hours before the biopsy. Simultaneously, light microscopy of the pineal parenchyma was performed in all groups of animals., Results: A slight but significant C-Fos increase was observed only in stress-exposed pinealocytes of rats after intranasal Epitalon infusions. C-Fos was irregularly distributed throughout pineal cells. In stress, the clusters of 5 10 cells containing C-Fos in their cytoplasm were detected. The dilation of capillaries and pericapillary space induced by an osmotic stress was partially reduced by the intranasal infusions of Epitalon., Conclusions: Tetrapeptide Epitalon is synthesised on the basis of the amino acid composition of pineal peptide extract Epithalamin. Epitalon modulates pineal secretion only under a stress impact but never in the norm. It prevents osmotic-stress-induced pathologic changes in the pineal parenchyma structure. Besides, the physiological activity of Epitalon seems to be mediated by the activation of protooncogenes in pinealocytes.

The authors investigated the pineal blood supply in the rat, including microvascularisation, using different methods of vascular corrosion cast technique and two methods of inspection: scanning electron microscopy (SEM) and light microscope (LM). The animals were divided into three groups and injected with two types of casting media. It was found that the pineal gland is highly vascularised. Arterial supply is from the branches of the medial posterior choroidal artery which originates from the posterior cerebral artery. All veins drain into the great cerebral vein directly without forming the pineal vein. However, we noticed a short venous trunk between the great cerebral vein and the confluence of the sinuses. This venous trunk had not been described in literature till now and does not have a name in anatomical nomenclature. The authors showed the relationship of the pineal gland to adjacent venous vessels.

Background: Pineal apoplexy is a rare apoplectic event in the pineal region with various possible causes. We report a case of massive hemorrhage in the pineal region associated with a cavernous angioma, and discuss the pathogenesis of pineal apoplexy., Case Description: An 11-year-old girl presented with nausea and vomiting persisting for 1 week. Neuroimaging revealed enlarged ventricles and a 4 cm round mass in the pineal region consistent with hematoma. Two weeks after cerebrospinal fluid drainage, the mass was totally removed via the occipital transtentorial approach. The postoperative course of the patient was uneventful. Magnetic resonance imaging after the operation confirmed two paraventricular lesions with surrounding hemosiderin rings, characteristic of cavernous angioma. Histologic examination showed large hematomas and numerous vascular spaces lined by a single layer of endothelium. The diagnosis was pineal apoplexy associated with cavernous angioma, based on the histologic and radiological findings., Conclusions: Pineal cavernous angiomas are extremely rare, with only fourteen cases reported previously. We recommend total removal of the causative lesion in cases of pineal apoplexy to prevent repeated bleeding or life-threatening massive hemorrhage.

The study showed the presence of NADPH-diaphorase containing structures in the pineal gland of the domestic pig. NADPH-diaphorase activity was found in the nerve fibers and in the endothelial cells of the vasculature. The nerve fibers were localized in the capsule, around the blood vessels as well as in the parenchyma. The positive staining was not observed in the pig pinealocytes.

After a short overview of the history of our knowledge of the pineal gland, its anatomy and its function, this work is primarily devoted to the relationships of the pineal gland to the nerve structures which delineate the pineal region. The complex surrounding blood vessels located in the quadrigeminal cistern are described with a special focus on the numerous venous trunks. Finally, the pineal blood supply is studied in three steps: (1) The arterial supply obtained through several groups of pineal arteries stemming mainly from the medial posterior choroidal arteries; (2) The venous drainage by the lateral pineal veins flowing, in most cases, into the cerebral vein of Galen; (3) The intrapineal vascular architecture with specific features concerning the central part of the gland highly vascularized by large sinusoid capillaries and its peripheral part poorly vascularized by small and fine blood vessels.

Kallikrein hydrolyzes various biologically active peptides, other than kininogens, such as vasoactive intestinal polypeptide (VIP), in vitro. Since kallikrein and VIP have been immunohistochemically shown to be present in the perivascular areas of the pineal gland, this study was designed to determine their topographic proximity in these glands, using immunohistochemical and immunoelectron microscopic double staining methods. Furthermore, since this gland is well-known to have a circadian rhythm, the kallikrein content was measured every 4 h, using a synthetic substrate, Pro-Phe-Arg-MCA, and an enzyme-linked immunosorbent assay (ELISA) to determine whether kallikrein has a circadian rhythm. The immunoreactivities of kallikrein and VIP were highly localized in the perivascular extracellular spaces and were virtually identical in distribution. The kallikrein content changed every 4 h and was high under light and low under dark conditions. The change was more evident when the synthetic substrate was used, and this rhythm was subtle on ELISA. VIP is also said to have a circadian rhythm in the pineal glands, being low under light and high under dark conditions, i.e., opposite to that of kallikrein. Since kallikrein degrades VIP in vitro, it is reasonable to speculate that pineal gland kallikrein is involved in the processing of VIP and possibly other biologically active peptides in the perivascular areas with a discernible circadian rhythm., (Copyright 1998 Elsevier Science B.V. All rights reserved.)

Background: The previous results regarding regional and day-night differences in pinealocyte size in rats are conflicting. The relationships between these differences and the vascularity and sympathetic innervation have scarcely been investigated., Methods: Wistar-King rats, kept under light/dark 12:12, were killed at midday or midnight in October. The nuclear density of pinealocytes in the superficial pineal was measured on the dorsoperipheral, dorsocentral, ventroperipheral, and ventrocentral regions at distal, middle, and proximal levels at daytime and nighttime. The total area of blood vessels per unit area at daytime and nighttime and total length of tyrosine hydroxylase (TH)-immunoreactive fibers per unit area at daytime were determined on the same regions at the same levels., Results: Pinealocyte size was larger toward the distal levels and in the periphery than in the center at any level. The area of blood vessels and length of TH fibers were also larger toward the distal levels; the former in the ventral region and the latter in the dorsal and ventral regions were larger in the periphery than in the center. Ventral pinealocytes, but not dorsal ones, showed day-night changes in size. Prominent day-night rhythms in area of blood vessels occurred in the ventral region, where TH fibers were more abundant than in the dorsal region., Conclusions: Pinealocyte size shows the distal to proximal and peripheral to central gradients, which may be related to the differential distribution of blood vessels and sympathetic fibers. Since pinealocytes and blood vessels, showing prominent day-night changes in size, are localized in the more richly innervated regions, sympathetic fibers may play an important role in controlling these rhythms.

We have used the NADPH-diaphorase enzyme histochemical technique to localize the enzyme nitric oxide synthase in the rat pineal gland. Some scattered NADPH-diaphorase positive pineal cells were present, mostly in the rostral part of the gland close to the pineal stalk. In addition, NADPH-diaphorase positive nerve fibers were located in the pineal capsule, in the connective tissue septae of the gland, and also intraparenchymally between the pinealocytes. Most nerve fibers were endowed with boutons en passage. These nerve fibers remained in the gland after bilateral removal of the superior cervical ganglia verifying a non-sympathetic nature of the NADPH-diaphorase positive nerve fibers. Pineal blood vessels also exhibited NADPH-diaphorase activity. The number and distribution of NADPH-diaphorase containing cells and nerve fibers were not affected by bilateral superior cervical ganglionectomy. Furthermore, animals sacrificed during day or night exhibited the same NADPH-diaphorase pattern. The present investigation provides the first morphological evidence for the presence of NADPH-diaphorase activity in rat pineal cells, suggesting an influence of nitric oxide on pineal metabolism. Furthermore, the presence of NADPH-diaphorase activity in the pineal blood vessels as well as in the perivascular nerve fiber suggests an influence of nitric oxide on the blood flow to the gland and/or the metabolism of the pineal cells adjacent to the blood vessels.

In this study, we analysed the microanatomy of the medial and lateral posterior choroidal arteries, which supply vital central nervous system structures to the brainstem and choroids plexus. We traced the anatomical course of the medial and lateral posterior choroid arteries, their origin, diameter, number of branches, length, and anatomical variations. Twenty-six human unfixed brains were injected through the vertebral and carotid arteries with silicon rubber. Fifty-one out of a total of 129 vessels were medial posterior, and 78 were lateral posterior choroidal arteries. We divided the medial posterior choroidal artery into three segments: around the brainstem, quadrigeminal-pineal, and choroidal. The mean length of the medial posterior choroidal artery was 77.6 +/- 15 mm on the right side, and 77.1 +/- 15 mm on the left; the mean outer diameter observed was 0.8 +/- 0.5 mm on the right side, and 0.8 +/- 0.4 mm on the left. The number of branches arising from the medial posterior choroidal arteries averaged 25 +/- 9. In the lateral posterior group, the mean length observed was 49.5 +/- 26 mm on the right, and 58.0 +/- 23 mm on the left. There were instances of duplication and triplication of the lateral posterior choroidal vessels. The outer diameter averaged 0.72 mm on the right, and 0.6 mm on the left. The posterior choroidal arteries are clearly an important vascular component. A comprehensive knowledge of their anatomy will aid the neurosurgeon during surgery of the brainstem, pineal region, and third ventricle, and will limit complications resulting from injury to these arteries.

Gross supply, microvascular patterns, and drainage routes of the pineal gland and its vascular relations with associated structures (dorsal sac, paraphysis, choroid plexus of the third ventricle) were studied by scanning electron microscopy of microvascular corrosion casts in 10 specimens of the freshwater turtle, Pseudemys scripta elegans. Light microscopy of tissue sections (one transverse and one longitudinal series) served to attribute cast vascular territories to anatomical structures. The tubular pineal gland body is supplied bilaterally by small branches of the saccular artery, a branch of the lateral choroidal artery. Branches of the diencephalic artery supply the pineal stalk. The pineal gland microvascular bed is a two-dimensional network that embraces the tubular gland. The network is made up mainly of venules with few true capillaries. Venules draining the ventral surface of the pineal gland body join those coming from the choroid plexus of the third ventricle and drain into the sagittal sinus. The less dense vascular network embracing the dorsal surface of the pineal body drains directly into the sagittal sinus. The pineal stalk drains into the diencephalic vein or directly into the sagittal sinus. No efferent (venous) vascular connections capable as transport route for pineal secretions toward surrounding telencephalic, diencephalic, or mesencephalic areas were found.

Postnatal development of the innervation of the porcine pineal gland by tyrosine hydroxylase-(TH-), dopamine-beta-hydroxylase-(D beta H), phenylethanolamine-N-methyltransferase-(PNMT-) and neuropeptide Y- (NPY-) immunoreactive (IR) nerve fibres was examined using the double-labelling immunohistochemical technique. TH-IR nerve fibres appeared in the pineal gland of new-born piglets and formed plexus in the capsula and connective tissue septa of the gland. In 20-day-old pigs and older ones, the nerve terminals branched off from the plexus and penetrated into adjacent parenchyma. The nerve fibres formed network; its density increased with age and depended on the region of the gland. In mature pigs, some differences in the innervation pattern between cortex and medulla were also observed. Most of TH-IR fibres were also D beta H- and NPY-positive. Some PNMT-positive fibres were noted in new-born piglets, but not in older animals. NPY-IR fibres were distributed in pattern overlapping that observed in the case of TH- and D beta H-IR fibres. Most of NPY-IR fibres were also positive for TH.

The blood vascularization in the pineal gland of the crow was investigated in detail using a vascular corrosion cast technique and by scanning electron microscopy. The pineal gland received two afferent arteries on either side, each artery arising from the A. cerebralis caudalis (CC) which supplied its branches to the hemisphere. The pineal gland of the crow was so highly vascularized as to be suggestive of its high metabolic and endocrine activities. The efferent veins drained into the Sinus occipitalis and the Sinus sagittalis dorsalis. There was a direct vascular connection between capillaries of the stalk of the gland and those of the Plexus choroideus.

The pineal organ of the golden hamster consists of deep and superficial portions which are connected to each other by a stalk. The permeability of capillaries for horseradish peroxidase (HRP) injected intravenously was examined in sections of entire portions of the gland that cut either along coronal or sagittal planes. Two distinct portions of the parenchyma, i.e., dorsal major and ventral minor ones, were found in the superficial gland. Most of the capillaries in the dorsal portion were of the continuous type of endothelium, whereas those in the ventral portion were fenestrated. In the dorsal portion, HRP readily crossed the endothelium, permeated the basal lamina, flowed into the perivascular connective tissue space and intruded into the intercellular clefts of the parenchyma. In contrast, HRP was not found to penetrate through the endothelium of the capillaries in the ventral portion to reach the perivascular area, thereby leaving the intercellular clefts of the parenchyma free of HRP. In the deep gland the capillaries were exclusively of the nonfenestrated type. Intravenously injected HRP was prevented from crossing the endothelium by the tight junction. In some areas, HRP penetrated through the capillaries in the pia mater, and crossed the outer limiting membrane to reach the intercellular clefts of the parenchyma and the basal lamina of the capillaries in the peripheral region of the deep pineal gland. The junctions between endothelial cells were not penetrated by HRP. The observations indicate that the type of capillary, absence of perivascular spaces, and permeability in the deep pineal are all similar to these factors in the general brain tissue; they differ from these in the superficial pineal gland, in which the dorsal portion shows characteristics found in other endocrine glands, but the ventral zone exhibits a unique situations: the presence of a blood-pineal barrier with a pericapillary connective tissue area.

The vascularization of the pineal complex in the lizard Tiliqua rugosa was investigated by vascular corrosion and latex casting techniques. The fine structure of the pineal capillaries was also studied by transmission electron microscopy. The pineal complex in T. rugosa consists of an elongated pineal gland proper and a separate, distinct parietal eye. The pineal complex derives an abundant blood supply from branches of the middle and posterior cerebral arteries. Scanning electron microscopy of vascular corrosion casts revealed a dense and extensive pineal capillary bed which drains ultimately into a wide longitudinal sinus suggesting an efficient pathway for the rapid removal of substances secreted by the gland. The parietal eye, which receives a unilateral left-sided blood supply from the unpaired anterior pineal artery, is shown to be a highly vascularized structure. The close morphological relationship between the pineal gland and dorsal sac, where the two structures apparently share the same blood vessels, suggests a functional relationship between them. The pineal capillaries are fenestrated with tight junctions between adjoining endothelial cells. Podia-like abluminal extensions of the endothelial cells were observed in close relation to unmyelinated nerve bundles. The basal margin of the pineal parenchyma is highly invaginated with thin finger-like cytoplasmic protrusions into the pericapillary space. Distinct bands of microfibrils form "struts" anchoring the pineal parenchyma to the endothelial wall. These features may have a role in the transfer of materials between the pineal gland and the blood stream.

The survival, revascularization, reinnervation, and recovery of function of transplanted rat pineal glands were studied following grafting into four different locations in pinealectomized rats. Pineal grafts were well vascularized by fenestrated capillaries. Pinealocytes in the grafts maintained high-metabolic activity. More nerve fibers and terminals were observed in the grafts within the anterior chamber of the eye than in the third cerebral ventricle and the pineal region (in situ transplantation). No fibers or terminals were found in grafts placed beneath the renal capsule. Nighttime serum melatonin levels increased significantly in pinealectomized rats with transplants into either the third cerebral ventricle or the anterior eye chamber. This increase might reflect graft reinnervation. Yet day-night differences in serum melatonin were observed only in host rats receiving transplants in the anterior eye chamber. In conclusion, pinealocytes survived transplantation into different locations and exhibited ultrastructural features indicative of active secretory processes; however, day-night differences in serum melatonin are only restored following transplants into the anterior eye chamber. Reinnervation of the grafts by the host superior cervical ganglion is necessary for this restoration.

Quantitative measurements of blood flow (BF) to skin and several other tissues were made using radioactive microspheres in conscious sheep. The sheep were from established flocks that had been selectively bred for greater (Fleece plus) or lesser (Fleece minus) wool production. The BF rate per unit area of wool-bearing skin was significantly greater in the Fleece plus (n = 9) than in the Fleece minus (n = 6) group, but the correlation between skin BF and the wool growth rate in individual animals was modest (r = .581). There was a strong, positive correlation (r = .813) between wool production and pineal BF. Other tissues that exhibited significant BF differences between the two groups included adrenal glands and fat, which were greater in Fleece plus sheep, and thyroid glands, reticulum, rumen, and extremity skin (non-wool-bearing), which were lesser in Fleece plus sheep.(ABSTRACT TRUNCATED AT 250 WORDS)

The structure and ultrastructure of the pineal gland of the degu or trumpet-tailed rat (Octodon degus), a rodent inhabiting tropical-equatorial areas, was examined under light and electron microscopy. On the basis of its form, size, and location, the pineal gland of the degu is classified as a proximal or "A" type. The connective tissue appeared poorly developed and the gland contained non-fenestrated capillaries. A single population of typical pinealocytes was found. In addition, a small number of glial cells and cells with electron dense bodies appeared scattered throughout the gland. Cells with dense granules were found isolated or forming small groups always in close proximity to blood vessels. Numerous sympathetic nerve fibers with small dense-core vesicles were found. Also, some myelinated nerve fibers were observed. The physiological significance of the presence of large electron-dense granules in some pineal cells and their particular location around the blood vessels in discussed.

Diagnosis and treatment of tumours and vascular malformations in the region of the pineal gland continue to challenge the neurosurgeon's skill. Due to vital vascular and brain structures in the region, microsurgical removal of such masses is often impossible. During the past nine years, we have managed 47 patients with pineal region mass lesions using stereotactic techniques for diagnosis and treatment. In order to determine further therapeutic options, 15 patients underwent stereotactic biopsy of pineal region tumours. In all patients, the histologic diagnosis obtained served to direct further therapy. Thirty-two patients were treated with stereotactic radio-surgery for pineal region tumours or vascular malformations. During the follow-up period, one patient underwent delayed microsurgical resection of a midbrain angiographically occult vascular malformation. No other patient required microsurgical intervention after a stereotactic procedure. In all 47 patients, no significant morbidity or mortality occurred after stereotactic biopsy or radiosurgery. Empiric treatment of pineal region tumours with fractionated radiation therapy is no longer warranted. Image-guided stereotactic technology provides a safe method to accurately diagnose and effectively treat selected pineal region masses. After definitive histologic diagnosis is established, proper treatment may be instituted. Options for treatment include stereotactic radiosurgery for selected tumours and vascular malformations, microsurgical resection of benign tumours or fractionated external beam radiation therapy for malignant germ cell and glial tumours. Stereotactic surgery should be the first option in the diagnosis and therapy of pineal region masses.