Should we resect peri-lesional hemosiderin deposits when performing lesionectomy in patients with cavernoma-related epilepsy (CRE)?

In this review, the authors perform a database search and summarize and discuss all eligible studies that provide (subgroup) analysis of the postoperative seizure outcome of patients with cavernoma-related epilepsy undergoing sole lesionectomy or lesionectomy including the hemosiderin rim. Based on the currently available data, the authors conclude that if surgical treatment of cavernoma-related epilepsy is performed, the peri-lesional hemosiderin should be resected. However, cases of eloquent or multiple localization or widespread hemosiderin deposit in which a complete resection is challenging should undergo a specific preoperative work-up.

Impact of porcine circovirus type 2 (PCV2) vaccination on boar semen quality and quantity using two different vaccines.

Porcine circovirus type-2 (PCV2) is widespread in domestic pig populations. It can be shed with boar semen, but the role boars have in epidemiology is still unclear. Vaccinating boars against PCV2 can reduce disease and virus load in semen, but may have unwanted side effects, that is, impairment of spermatogenesis. Therefore, the aim of this study was to investigate the effect and impact of two different PCV2 vaccines on boar semen quality and quantity. Healthy normospermic Large White boars in three groups of 12 each were vaccinated with either Circovac, Ingelvac CircoFLEX, or received NaCl. Eight ejaculates were collected starting 1 week after vaccination and assessed for quantitative traits. In general, sperm quantity and quality parameters did not change due to the vaccination (P > 0.05). Only DNA integrity between the Circovac and control group was P < 0.05 but remained at a low level (<2%). One boar showed clinical signs with body temperature up to 39.9 °C and went off feed. For this animal, a clear relation between vaccination, fever period, and impaired sperm quality could be observed. The results indicate that both vaccines did not have a major impact on sperm quality or quantity. Therefore, vaccination of boars against PCV2 seems to be feasible. However, one boar treated with the oil-based vaccine showed a temporarily impaired semen quality after elevated body temperature after vaccination. Thus, possible systemic reactions and the subsequent impact on sperm quality should be taken into account when choosing a PCV2 vaccine for boars.

Fibrillary structure is key for hemostasis: a similar effect of collagen fleece and oxidized cellulose on experimental hemorrhagic brain injury.

BACKGROUND: The choice of the ideal hemostatic agent for intraoperative cerebral bleeding is under continuous debate. Our aim was to assess the influence of such materials on bleeding time in hemorrhagic cerebral contusions. We compared oxidized regenerated cellulose in fibrillar form (ORC) to microfibrillar collagen fleece (CF) in an experimental study. METHODS: N=50 Sprague Dawley rats underwent a bilateral craniectomy. 3 separate standardized superficial cortical impacts were inflicted using a high-speed drill. Immediately after lesion placement, each of the 3 lesions was covered with (a) nothing (control), (b) ORC, or (c) CF. We observed the 3 lesions with a surgical microscope. The bleeding times were recorded for each cerebral lesion and compared using ANOVA test. RESULTS: All traumatic lesions produced significant bleeding. The statistical analysis showed a clear reduction in bleeding time for groups treated with either ORC or CF compared to the control group. Lesions covered with ORC and CF showed no significant difference with regard to bleeding time. CONCLUSIONS: ORC and CF significantly reduce blood loss from hemorrhagic contusions. Our data suggest that they effectively reduce bleeding time. We advocate the use of hemostatic material for limiting bleeding from superficial cortical lesions.

Simultaneous bedside assessment of global cerebral blood flow and effective cerebral perfusion pressure in patients with intracranial hypertension.

BACKGROUND: We examined a bedside technique transcerebral double-indicator dilution (TCID) for global cerebral blood flow (CBF) as well as the concept of effective cerebral perfusion pressure (CPP(eff)) during different treatment options for intracranial hypertension, and compared global CBF and CPP(eff) with simultaneously obtained conventional parameters. METHODS: Twenty-six patients developing intracranial hypertension in the course of traumatic brain injury or subarachnoid hemorrhage were prospectively analyzed using a combined assessment during elevated ventilation (n = 15) or osmotherapy (hypertonic saline or mannitol). For calculation of global CBF, injections of ice-cold indocyanine green boluses were performed and temperature and dye concentration changes were monitored in the thoracic aorta and the jugular bulb. CBF was then calculated according to the mean transit time principle. Estimation of CCP, the arterial pressure at which cerebral blood flow becomes zero, was performed by synchronized registration of corresponding values of blood flow velocity in the middle cerebral artery and arterial pressure and extrapolation to zero-flow velocity. CPP(eff) was calculated as mean arterial pressure minus critical closing pressure (CPP(eff) = MAP(c) - CCP). RESULTS: Elevated ventilation causes a decrease in both ICP (P < 0.001) and CBF (P < 0.001). While CPP(conv) increased (P < 0.001), CPP(eff) decreased during this observation (P = 0.002). Administration of osmotherapeutic agents resulted in a decrease of ICP (P < 0.001) and a temporary increase of CBF (P = 0.052). CPP(conv) and CPP(eff) showed no striking difference under osmotherapy. CONCLUSION: TCID allows repeated measurements of global CBF at the bedside. Elevated ventilation lowered and osmotherapy temporarily raised global CBF. In situations of increased vasotonus, CPP(eff) is a better indicator of blood flow changes than conventional CPP.

Three-dimensional time-of-flight MR angiography at 3 T compared to digital subtraction angiography in the follow-up of ruptured and coiled intracranial aneurysms: a prospective study.

INTRODUCTION: Since digital subtraction angiography (DSA) carries a low risk of morbidity, and is associated with patient discomfort and higher cost, our objective was to determine whether high-resolution 3-D time-of-flight MR angiography (TOF-MRA) at 3 T may replace DSA in the follow-up of patients after coiling of an intracranial aneurysm. METHODS: This prospective study included 50 consecutive patients with a ruptured and subsequently coiled intracranial aneurysm. All patients were followed up at a mean of 14 months after coiling with DSA and high-resolution 3-D TOF-MRA at 3 T generating 0.02 mm3 isotropic voxels. One examiner used DSA and TOF-MR angiograms to assess the need for and risk of retreatment; these data were used to calculate intermodality agreement. Another two examiners independently assessed aneurysm occlusion by DSA and TOF-MRA according to the Raymond scale; these data were used to calculate interobserver agreement. RESULTS: Discrepancies between DSA and TOF-MRA were found in three patients (intermodality agreement kappa=0.86). While DSA indicated complete aneurysm occlusion, TOF-MRA showed small neck remnants in the three patients. Coils on all DSA projections obscured these three neck remnants. Interobserver agreement was higher for DSA (kappa=0.82) than for TOF-MRA (kappa=0.68), which was in part due to the complexity of the information provided by TOF source images and reconstructions. CONCLUSION: 3-D TOF-MRA at 3 T is not only an adjunctive tool but is ready to replace DSA in the follow-up of patients with previously coiled intracranial aneurysms. Additional DSA may only be performed in complex and not clearly laid out aneurysms.

Gene expression profiling suggests primary central nervous system lymphomas to be derived from a late germinal center B cell.

To characterize the molecular origin of primary lymphomas of the central nervous system (PCNSL), 21 PCNSLs of immunocompetent patients were investigated by microarray-based gene expression profiling. Comparison of the transcriptional profile of PCNSL with various normal and neoplastic B-cell subsets demonstrated PCNSL (i) to display gene expression patterns most closely related to late germinal center B cells, (ii) to display a gene expression profile similar to systemic diffuse large B-cell lymphomas (DLBCLs) and (iii) to be in part assigned to the activated B-cell-like (ABC) or the germinal center B-cell-like (GCB) subtype of DLBCL.

Cranioplasty for large skull defects with PMMA (Polymethylmethacrylate) or Tutoplast processed autogenic bone grafts.

OBJECTIVE: Aim of the study was a comparison of cranioplasty using the Tutoplast technology for autogenic bone processing and conventional polymethylmethacrylate (PMMA) calvarial re- construction. PATIENTS AND METHODS: A retrospective analysis was carried out in a consecutive series of 61 plastic reconstructions for skull defects, the largest measuring more than 12 cm. Cranioplasty was either performed with PMMA or with the patient's own bone graft which had been recycled using the Tutoplast process. RESULTS: 36 patients with a mean age of 44 (range 10-68) years underwent freehand PMMA cranioplasty following craniectomy for increased intracranial pressure (19 patients, 52.8%), infection (15 patients, 41.7%), or traumatic bone destruction (2 patients, 5.6%). Bilateral procedures were performed in 10 patients (27.8%). Mean follow-up was 44 months. Four patients (11.1%) died, 14 (38.9%) remained severely disabled, and 18 (50%) made a satisfactory recovery. Two patients (5.6%) had PMMA-related complications and required removal. 26 patients exhibited at least satisfactory cosmetic results (83.9%), in 5 patients the results were not satisfactory (16.1%) and in 5 the results are unknown. Twenty-five patients with a mean age of 42 (range 2-68) years received Tutoplast processed autografts following craniectomy for elevated intracranial pressure. Bilateral procedures were performed in 3 patients (12%). Mean follow-up was 15 months. One patient (4%) died, 18 (72%) remained severely disabled, and 6 (24%) made a satisfactory recovery. All patients had satisfactory cosmetic results, but 2 patients (8.3%) required removal at a later stage, one due to infection (4.2%) and one for bone resorption (4.2%). In the 18 patients with follow-up >0.5 years significant resorption occurred in all 5 children and adolescents (100%) and in two adult patients (15.4%). CONCLUSION: Cosmetic results were more satisfactory with Tutoplast processed autografts, and the operating time for unilateral surgery was shorter. Complication rates were similar. Resorption occurred in all children and adolescents, but was rare in adults. Thus, Tutoplast processed autogenic bone grafts can be a reasonable alternative to other methods of cranioplasty in adult patients with large craniotomy defects. Cranioplasty in children and adolescents remains an unsolved problem.

Sensory gating of auditory evoked and induced gamma band activity in intracranial recordings.

Oscillatory activity in the gamma band range (30-50 Hz) and its functional relation to auditory evoked potentials (AEPs) is yet poorly understood. In the current study, we capitalized on the advantage of intracranial recordings and studied gamma band activity (GBA) in an auditory sensory gating experiment. Recordings were obtained from the lateral surface of the temporal lobe in 34 epileptic patients undergoing presurgical evaluation. Two kinds of activity were differentiated: evoked (phase locked) and induced (not phase locked) GBA. In 18 patients, an intracranial P50 was observed. At electrodes with maximal P50, evoked GBA occurred with a similar peak latency as the P50. However, the intensities of P50 and evoked GBA were only modestly correlated, suggesting that the intracranial P50 does not represent a subset of evoked GBA. The peak frequency of the intracranial evoked GBA was on average relatively low (approximately 25 Hz) and is, therefore, probably not equivalent to extracranially recorded GBA which has normally a peak frequency of approximately 40 Hz. Induced GBA was detected in 10 subjects, nearly exclusively in the region of the superior temporal lobe. The induced GBA was increased after stimulation for several hundred milliseconds and encompassed frequencies up to 200 Hz. Single-trial analysis revealed that induced GBA occurred in relatively short bursts (mostly <<100 ms), indicating that the duration of the induced GBA in the averages originates from summation effects. Both types of gamma band activity showed a clear attenuation with stimulus repetition.

On the difficulty of neurosurgical end of life decisions.

OBJECTIVE: To analyse the process of end of life decisions in a neurosurgical environment. METHODS: All 113 neurosurgical patients, who were subject to so called end of life decisions within a one year period were prospectively enrolled in a computerised data bank. Decision pathways according to patient and physician related parameters were assessed. RESULTS: Leading primary diagnoses of the patients were traumatic brain injury and intracranial haemorrhage. Forty-five patients had undergone an emergency neurosurgical operation prior to end of life decision, N = 69 were conservatively treated, which included intracranial pressure recording, or they were not offered neurosurgical care because of futile prognosis. N = 111 died after a median of two (zero to nine) days. Two, in whom the end of life decisions were revised, survived. Clear decisions to terminate further treatment were made by a senior staff member on call being informed by the senior resident on call (27.4%), difficult decisions on the basis of extensive round discussions (71.7%), and very difficult decision by an interdisciplinary ethical consult (0.9%). Decisions were further substantiated by electrophysiological examinations in N = 59. CONCLUSION: End of life decisions are to be considered standard situations for neurosurgeons. These decisions may reach a high rate of "positive" prediction, if substantiated by electrophysiological examinations as well as on the grounds of clinical experience and respect for the assumed will of the patient. The fact that patients may survive following revision of an end of life decision underlines the necessity for repeated reassessment of these decisions. Ethical training for neurosurgeons is to be encouraged.

[The trend sport snowblading and its risks]. / Der Trendsport Snowblading und seine Risiken.

The study analysed the results of an examination of 3557 skiing, snowboarding and snowblading injuries treated at the Department of Trauma Surgery at the Klinikum Garmisch-Partenkirchen in winter seasons 99/00 through 02/03. In this study group, a total of 70 injuries occurred while snowblading. These injuries are compared to the remaining injuries resulting from skiing, carving or snowboarding accidents. This study intends to contribute to the tracking and recording of injuries occurring during snowblading, a sport that is popular but not yet well-addressed in medical literature. The results show that snowblading injuries are similar to those of skiing, but different from those attributable to snowboarding, particularly with regard to the affected parts of the body and injury patterns. Acrobatic jumps increase significantly the risk of fractures of the lower extremities. However, ruptures of ligaments, especially of the ACL, are seen more rarely in snowblading than in carving or conventional skiing. Distorsions, on the other hand, are observed significantly more often among snowbladers when compared with carvers and snowboarders. Release bindings for snowblades could reduce the risk of injuries.

Operation for delayed symptomatic brain oedema after treatment of an arteriovenous malformation by embolization and radiosurgery.

A patient with a Spetzler-Martin-grade-III AVM, initially embolized and then stereotactically irradiated, who - with a latency of several months - showed progressive neurological deterioration, is reported. Magnetic resonance imaging revealed enormous ipsilateral brain oedema, which did not respond to dexamethasone. Upon further neurological deterioration the former AVM nidus plus an adjacent rim of brain tissue were removed and the patient recovered considerably. It is concluded that embolization in conjunction with irradiation may impair the blood-brain-barrier with resulting long-term oedema in the surrounding brain, and that surgical treatment should be considered in selected cases.

Sensory gating in the human hippocampal and rhinal regions.

OBJECTIVE: The objective of this work was to ascertain if sensory gating can be demonstrated within the human medial temporal lobe. METHODS: Eight patients with intractable epilepsy with depth electrodes implanted in the medial temporal lobe for pre-surgery evaluation underwent evoked response recording to auditory paired-stimuli (S1-S2). Each of the eight subjects had a diagnosis of left medial temporal lobe epilepsy (MTLE). RESULTS: Data from the non-focal right hippocampi revealed a large negative response on S1 (starting at about 190 ms and lasting for approximately 300 ms from stimulus onset). Rhinal region recordings revealed a positive response (starting at about 240 ms with a rapid incline, followed by a long-lasting decline). A significant attenuation of both responses to S2 stimuli was observed. CONCLUSIONS: Data are suggestive of an involvement of the human medial temporal lobe in the processing of simple auditory information which occurs in a time frame later than the neocortical auditory evoked components. The exact role of these anatomical structures in the sensory gating process remains to be defined. SIGNIFICANCE: This study provides the first evidence of an activation of the rhinal cortex after simple auditory stimulation and provides new evidence that the activation of the medial temporal lobe structures occurs at a later stage than that of the neocortex.

Fusion of MRI and CT with subdural grid electrodes.

In patients with drug-resistant focal epilepsies subdural grid electrodes may be implanted to determine the seizure onset zone and eloquent cortex areas. Since the spatial relationship of the grid to the underlying brain is poorly visualized on MRI, we co-registered MRI before and CT after implantation of subdural grid electrodes. In this study we sought an appropriate algorithm to combine both imaging modalities. We compared six different co-registration algorithms including surface-oriented, mutual information-based and landmark-based methods. The resulting overlay matrices were analyzed by calculating rotational and translational shifts and by judging co-registered MRI and CT scans visually. A brain surface oriented method had the lowest rotational (axial 0.7 +/- 0.6 degrees; coronal 1.7 +/- 1.1 degrees; sagittal 1.9 +/- 1.8 degrees) and translational shifts (3.7 +/- 1.3 mm). It was judged visually to be the best, had a low intra- and inter-observer variability, and lasted approximately 15 minutes. This algorithm is recommended when co-registering MRI before and CT after implantation of subdural grid electrodes. Skin-, voxel-, and landmark-based algorithms are less accurate, which is most likely due to postsurgical deformation of extra- and intracranial soft tissue.

Clonal evolution as pathogenetic mechanism in relapse of primary CNS lymphoma.

Comparative investigation of immunoglobulin (Ig) heavy chain gene rearrangements and DNA sequence analyses of a primary lymphoma of the CNS (PCNSL) and its recurrence revealed that both tumors used the same Ig gene segment. In addition to shared somatic mutations, the primary and the recurrent PCNSLs harbored somatic mutations unique to each tumor. Clonal evolution rather than subclone selection appears to underlie the development of tumor recurrence in this case.

Immediate postoperative angiography after aneurysm clipping--implications for quality control and guidance of further management.

BACKGROUND: To determine the impact of postoperative angiography after aneurysm clipping on quality control and further management. METHODS: A recent consecutive series of n = 296 patients (186 females, 110 males, mean age 51 yrs) who underwent 324 craniotomies to clip 384 aneurysms was reviewed. New irregularities on postoperative angiographies were categorized as unrelated (e. g. vasospasm) or related (= vessel occlusion/residuum) to clipping and expected or unexpected by the surgeon. Therapies prompted by these findings as well as subsequent negative sequelae were analyzed. Factors related to negative events were identified by logistic regression (p < 0.05). RESULTS: Twenty-six (8%) unrelated findings prompted medical or intravascular therapy. Of 36 (9.4%) clip-related findings (n = 17 occlusions, n = 19 residua), 14 (3.6%) were unexpected (n = 9 occlusions, n = 5 residua). This was followed by 9 (2.3%, n = 4 occlusions, n = 5 residua) clip readjustments and 6 aggressive medical therapies. Nine patients were scheduled for angiographic follow-up, of which in five performed so far no change of aneurysm remnants was noted. Permanent sequelae from vessel occlusion occurred in 9 cases. Major premature rupture (p < 0.005), giant size/fusiform configuration (p < 0.001), posterior circulation aneurysms (p < 0.05) and ophthalmic segment location (p < 0.008) were significantly related to adverse postoperative findings. The use of microvascular Doppler significantly reduced the rate of unexpected vessel occlusion (3.3 vs. 0.9%). CONCLUSIONS: Apart from the need for quality control in aneurysm clipping--especially with respect to coiling--our results stress the importance of postoperative angiography, because a small, but significant subset of patients will benefit from immediate intervention and/or deserves long-term follow-up.

Hippocampal function and visual object processing in temporal lobe epilepsy.

Limbic event-related potentials related to verbal but not to visual recognition memory have been found to be attenuated within the epileptic hippocampus of patients with temporal lobe epilepsy (TLE). To identify hippocampal contributions to visual processing and memory we recorded intracranial ERPs directly from within the epileptic and the non-epileptic hippocampus in 12 patients with unilateral TLE during a visual object decision and naming task. While the non-epileptic hippocampus differentiated reliably between real and nonsense objects, this effect was completely eliminated within the epileptic mesial temporal lobe. This finding suggests that the hippocampus proper contributes to the semantic processing of visual objects and may help to explain visual memory deficits in TLE.

[Dangers in skiing]. / Gefahren beim Carvingskifahren.

The current study deals with the results of the examination of 685 patients, who were treated in the department of traumatology in the KKH Garmisch-Partenkirchen during the winter season 99/00 and 00/01. The study included 259 injured carvers (120 female, 139 male) with an average age of 33.9 years and 426 injured conventional skiers (212 female, 214 male) with an average age of 33.2 years. The aim of the investigation was to compare both ski groups concerning injuries, the pathomechanism and the skiing experience. The results of the investigation showed that the knee injuries of carvers were more severe than in the conventional skiers. The difference was significant (p < 0.05).

Results for microsurgical removal of tentorial meningiomas.

OBJECTIVE: Growth patterns of tentorial meningiomas are related to the deep cerebral venous system and to cranial nerves IV-XI. Localization and surgical aggressiveness are decisive for the outcome to be expected. PATIENTS AND METHODS: n = 25 patients (22 f, 3 m), aged from 26-77 (mean: 56.4) years underwent microsurgical removal of their tentorial meningioma. Tumor size was as follows: n = 11 < 3 cm, n = 6 3-5 cm, n = 8 > 5 cm. The median of the preoperative Karnofsky scores was 90. The operative approaches chosen were suboccipital in n = 14, subtemporal in n = 6, occasionally a combined supra- and infratentorial approach was chosen. Data regarding surgery, histology and postoperative course were available through the patient's charts and through outpatient clinic. RESULTS: n = 20 (80%) of the tumors were rated WHO grade I, n = 5 (20%) WHO grade II. Tumor removal according to Simpson was degrees I in n = 9 (36%), degrees II in n = 14 (56%), degrees III in n = 2 (8%). Mortality was 0%. In n = 6 patients (24%) neurological worsening, mainly due to transient cranial nerve deficits was noted. Surgical complications (CSF fistula, wound healing problems) occurred in n = 5 patients (20%). The median of the postoperative Karnofsky scores on last follow up was 90 after a median of 41.9 months. Two patients (8%), one of whom underwent reoperation developed tumor recurrency during follow up. CONCLUSIONS: Neurological deficits following microsurgical removal of tentorial meningiomas are transient in the majority of patients. The apparently high rate of incomplete tumor resection (app. 60% Simpson grades II and III) is due to the close topographical relationship of these tumors with important neurovascular structures. Thus, the operative strategy should not be excessively aggressive, but rather take into account the option to observe residual tumor or to apply additional stereotactic convergent beam radiation in selected cases.

Vertebral artery injury after cervical spine trauma: a prospective study.

OBJECTIVES: Vertebral artery (VA) -injury is rarely symptomatic and can therefore easily be overlooked. However, thromboembolic complications may result in permanent morbidity or mortality due to brainstem ischemia and infarction. In this prospective study a standardized protocol for the diagnosis and management of VA-injury following blunt cervical spine trauma with subluxation or fractures affecting the transverse foramen was evaluated. METHODS: During a 48 months period 31 (12 female, 19 male; mean age 44.2 years) of 119 patients with blunt cervical spine trauma were suspicious for VA-injury and subjected to a predefined radiological work-up. Selective digital subtraction angiography (DSA) was performed at admission in 31 patients. For comparison magnetic resonance angiography (MRA) was added within 2 days in 7 patients. RESULTS: The incidence of VA injury detected by DSA (n = 5) was 4% in all types of blunt cervical spinal injury, 16% in cases suspicious for VA injury, i.e. cases with mono- or bifacet dislocation and/or cases with fractures extending into the transverse foramen. Unilateral VA-stenosis was found in 4 and VA-occlusion in one patients. In one case a VA-stenosis by an intimal flap after transverse foramen fracture was detected by DSA but not by MRA. In 2 patients with VA injury headache occurred without signs of vertebro-basilar insufficiency. All 5 patients with VA-injury were treated with anticoagulation without complications or side effects. 14 of 31 patients which had DSA/MRA had unstable spine conditions and were treated surgically within 4 days after admission. CONCLUSION: The subgroup of patients with dislocation or fracture related stenosis of the transverse foramen should undergo early angiography for establishment of anticoagulation to prevent thromboembolic complications. It appears that the radiological diagnosis of VA-insufficiency is more sensitive than clinical findings, which rarely indicate VA-insufficiency. In this series one VA injury was overlooked with MRA.

Human herpes virus-8 is not associated with primary central nervous system lymphoma in HIV-negative patients.

Primary central nervous system lymphomas (PCNSL) are derived from germinal center B cells. Recent molecular studies indicate that the tumor cells or their precursors have experienced antigenic stimulation. Attractive candidates for such antigens are pathogens with the capacity to reside in the brain. The aim of the present study was to evaluate whether human herpes virus (HHV)-8 is involved in the pathogenesis of PCNSL. A series of 46 PCNSL, 31 from HIV-negative and 15 from HIV-positive patients, were analyzed using various molecular biological and immunological approaches. Nested PCR with two different protocols unequivocally demonstrated that PCNSL from HIV-negative patients did not harbor HHV-8 DNA. Among AIDS-associated PCNSL, HHV-8 DNA was found in only 1 tumor. In situ hybridization studies revealed that the lymphoma cells were HHV-8 negative in all cases. Single small mononuclear cells, most likely corresponding to bystander lymphocytes, were identified as the cellular source of HHV-8 in the HIV-positive patient with an HHV-8 PCR signal. These studies largely rule out a role for HHV-8 in the pathogenesis of PCNSL in both HIV-negative as well as HIV-positive patients.