Recovery of adrenal function after chronic secondary adrenal insufficiency in patients with hypopituitarism.

OBJECTIVE: Previous studies have reported recovery of secondary adrenal insufficiency (SAI) in patients with pituitary disorders, generally immediately after pituitary surgery; however, data regarding recovery of long-term SAI are lacking. We conducted a study to assess the longer term recovery rate of SAI in patients with pituitary disorders. METHODS: We identified all SAI patients in the Halifax Neuropituitary Database from 1 November 2005 to 30 September 2014, who had required glucocorticoid therapy for ≥3 months, and had a minimum follow-up of 6 months. Patients with ACTH-secreting adenomas, those receiving glucocorticoids only in the routine peri-operative period for pituitary surgery and those on glucocorticoids for nonpituitary conditions were excluded. SAI was defined as either basal serum cortisol < 130 nm and/or a subnormal cortisol response to ACTH-(1-24) stimulation test or insulin tolerance test response. RESULTS: Fifty-one patients fulfilled the criteria. Nine (17·6%) patients had complete recovery of SAI over a median of 20 months (range: 8-51) after initiating glucocorticoid replacement. Patients with smaller tumour size had increased likelihood of hypothalamic-pituitary-adrenal (HPA) axis recovery, whereas those with secondary hypogonadism or growth hormone deficiency were less likely to recover. Those with initial cortisol >175 nm had an almost one in two chance of recovery. CONCLUSION: Results from our study show that approximately one in six patients with SAI recover adrenal function, even up to 5 years after diagnosis. We recommend that patients with SAI undergo regular testing to assess recovery in order to prevent unnecessary glucocorticoid therapy.

Effects of epidermal growth factor and erythropoietin on Müller glial activation and phenotypic plasticity in the adult mammalian retina.

Retinal Müller glia have received considerable attention with regard to their potential to function as quiescent retinal precursors. Various activation strategies induce characteristic features of retinal progenitor cells in Müller glia; however, these are often accompanied by hallmark features of reactive gliosis. We investigated the effects of an intravitreal injection of epidermal growth factor (EGF), a known mitogen, and erythropoietin (EPO) on activation and expression of developmental phenotypes within the adult retina. Using thymidine-analogue labeling as well as immunocytochemical and confocal analyses, we assayed the responses of retinal cells exposed to intravitreal administration of either EGF or EPO. We report that adult Müller glia incorporate bromodeoxyuridine (BrdU) and undergo a process of nuclear translocation to ectopic retinal layers following exposure to EGF. These cells survive within the retina for at least 23 days and express the developmental markers Pax6 and Chx10 as well as nestin and glial fibrillary acidic protein. Furthermore, we demonstrate that cotreatment with EGF and EPO suppresses aspects of EGF-induced glial reactivity, alters the retinal distribution of BrdU-positive nuclei, and serves to regulate the expression of developmental phenotypes seen in these cells. These data further our understanding of Müller cell responsiveness to intravitral, combinatorial growth factor treatments.

Changes in Musashi-1 subcellular localization correlate with cell cycle exit during postnatal retinal development.

RNA-binding proteins, and in particular, the Musashi genes, function as essential regulators of progenitor functioning in both the developing and adult organism. In this report, we characterize the differential subcellular distribution of Musashi-1 in cells engaged in either proliferating or differentiating contexts in the developing mouse retina, and in cultured Müller glia. During retinal cell differentiation, Musashi-1 immunoreactivity shifts from exclusively cytoplasmic in retinal progenitor cells, to predominantly nuclear localization in differentiating neurons. This nuclear shift is transient, with localization in the adult retina becoming predominantly perinuclear and cytoplasmic in Müller glia and photoreceptors. A correlation between cell cycle progression and subcellular distribution of Musashi-1 is observed in passageable, adult Müller glial cells in vitro. Furthermore, treatment of Müller cultures with neuron-promoting differentiation media induces asymmetric cytoplasmic Musashi-1 immunoreactivity in dividing daughter cells. The observed shifts in subcellular Musashi-1 localization are consistent with contrasting roles for Musashi-1 during cell proliferation and differentiation. These data provide evidence that nuclear, and cytoplasmic sequestering of Musashi-1 in retinal cells is context-specific, and may contribute to downstream functioning of Musashi-1.

Dietary intake estimate for perfluorooctanesulphonic acid (PFOS) and other perfluorocompounds (PFCs) in UK retail foods following determination using standard addition LC-MS/MS.

The analysis of 252 food samples (UK-produced and imported) purchased from a variety of retail outlets in the UK was undertaken for the presence of perfluorooctanesulphonic acid (PFOS), perfluorooctanoic acid (PFOA) and nine other perfluorocompounds (PFCs). A limit of quantification (LOQ) of 1 microg/kg was achieved for all target analytes, in all samples. Standard addition was used for quantification of PFC levels. All 11 of the targeted PFCs were detected in 75 individual food items. In 70% of the samples, including all meat other than offal, none of the analytes were present above the LOD. The highest levels found were 59 microg/kg perfluorooctanesulphonic acid (PFOS) and 63 microg/kg total PFCs (SigmaPFCs) in an eel sample, and 40 microg/kg PFOS (62 microg/kg SigmaPFCs) in a whitebait sample. The highest level in an offal sample was 10 microg/kg, in a wild roe deer liver. There were six samples with SigmaPFCs >15 microg/kg (fish, shellfish, crustaceans), a further seven samples with SigmaPFCs ranging 11-15 microg/kg (including a liver), nine with SigmaPFCs ranging 6-10 microg/kg (fish and livers), 31 with SigmaPFCs in the range 2-5 microg/kg (including kidneys, popcorn and processed peas) and a further 22 with SigmaPFCs close to the LOD of 1 microg/kg (including eggs and potatoes). These concentrations indicate that UK consumers are being exposed to a low level of PFC contamination from food. The estimated upper bound dietary intake of 10 ng/kg bodyweight (bw)/day of PFOS for average adult consumers is well below the 0.15 microg (150 ng)/kg bw tolerable daily intake (TDI) set by the European Food Safety Authority. The lower bound adult dietary intake estimate of 1 ng/kg bw/day is similar to estimates undertaken and reported in countries such as Canada, Germany and Spain.

Neural progenitor potential in cultured Müller glia: effects of passaging and exogenous growth factor exposure.

The Müller radial glial cell is the principal support cell of the adult mammalian retina. Recent reports suggest that these cells retain the capacity to proliferate, express phenotypes reminiscent of retinal progenitor cells (RPC) and generate neuron-like progeny. We isolated rodent Müller cells and generated cultures that could be passaged under conditions used in neural stem/progenitor cell colonies. We demonstrate that during the early period of primary culture, Müller glia proliferate into sphere colonies and express a select regimen of phenotypes normally seen in RPCs. This effect correlates temporally with the loss of retinal neurons post-dissection. When chronically maintained in vitro, Müller cells can be repeatedly passaged, and up-regulate early RPC phenotypes that are suggestive of cellular de-differentiation. Furthermore, exposure of Müller glial cultures to differentiating conditions containing growth factors stimulates Müller glia to up-regulate phenotypes associated with retinal neurons. These data provide further evidence that isolated, adult Müller glia retain functional and phenotypic features of RPCs.

Determination of phytoestrogens in dietary supplements by LC-MS/MS.

Labelling data quantifying the exact content of individual phytoestrogen analytes in dietary supplements are generally poor. As these products are commonly used in the management of menopause symptoms, any clinical benefits would be dependent on the exact dosage of isoflavones received. Well-established extraction procedures and updated isotope dilution mass spectrometry liquid chromatography coupled with tandem mass spectrometry detection (LC-MS/MS) have been used to accurately quantify the concentrations of ten common isoflavones in 35 dietary supplement samples on sale in the UK, Canada and Italy. Concentration-specific ionization suppression is described for biochanin A and formononetin. All supplements contained phytoestrogens. The soya isoflavones (genistein, daidzein, glycitein) were present in all products and the majority also contained the red clover isoflavones (biochanin A, formononetin) and some the Kudzu isoflavones (daidzein, puerarin). The content of total isoflavones per dose ranged from <1 to 53 mg. Trace amounts of coumestrol were found in six products. Other less common analytes, the prenylnaringenins (6-prenylnaringenin, 8-prenylnaringenin, 6,8-diprenylnaringenin) were not found in any of the products. Only 14 of 35 supplements were found to deliver more than or equal to 40 mg day(-1) of aglycone isoflavones, a consensus dose value recognized as delivering therapeutic benefit. Eleven did not match label claims. Six delivered less than 10 mg day (-1) of isoflavones. There has been little improvement in the overall quality of industry labelling in the five years since this was last investigated. Consequently, the public, retailers and healthcare professionals should consider using standardized isoflavone supplements, which are supported by analytical measurements.

The neural cell adhesion molecule is necessary for normal adult retinal ganglion cell number and survival.

Retinal ganglion cells (RGCs) undergo apoptotic death in predictable time-dependant manners during development and as a consequence of injury. Recently, synthetic neural cell adhesion molecule (NCAM) agonists have been shown to provide neuroprotective support. Within the adult mouse retina, NCAM has been localized on all neurons and glia; however, no functional role has been determined. Using adult NCAM-/- mice, we directly tested the potential influence of NCAM on neuron survival in vivo and observed that, in NCAM-/- retinas, RGC densities are greater, RGC loss after injury is earlier and target tissue significantly influences adult RGC survival, all in contrast to wild-type retinas. Collectively, our results indicate that NCAM may play a vital role in regulating the developmental change in the effectiveness of local versus target-derived RGC trophic support and that, in the adult, endogenous NCAM influences the total number of CNS neurons and their survival following injury.

Injury to retinal ganglion cell axons increases polysialylated neural cell adhesion molecule (PSA-NCAM) in the adult rodent superior colliculus.

The adult mammalian central nervous system (CNS) exhibits a limited regenerative response to injury. It is well established that polysialylated neural cell adhesion molecule (PSA-NCAM) contributes to nervous system plasticity. In the visual system, PSA-NCAM participates in retinal ganglion cell (RGC) axon growth during development and specifically influences RGC innervation of its principle target tissue, the superior colliculus (SC). The goals of this study were to determine whether PSA-NCAM is expressed in the normal adult mouse SC and to evaluate PSA-NCAM expression following RGC injury. In the normal rostral, but not caudal, SC we find that PSA-NCAM is present in the retinorecipient layers; however, PSA-NCAM and RGC axons do not co-localize. In the deeper collicular layers, PSA-NCAM is observed as several distinct patches that occur at the same depth along the medial-lateral axis throughout the colliculus. RGC axotomy denervates predominantly the contralateral colliculus, where increased PSA-NCAM levels are seen at 7 and 10 days after the injury. Further evaluation of the retinorecipient layers of the partially denervated SC reveals that some intact CTB-traced RGC axons (less than 5%) labeled from the ipsilateral eye do co-localize with PSA-NCAM. This study is the first characterization of PSA-NCAM expression in the normal and partially denervated adult SC and may indicate that PSA-NCAM is involved in attempted visual system remodeling after injury.

Target-derived neurotrophins may influence the survival of adult retinal ganglion cells when local neurotrophic support is disrupted: Implications for glaucoma.

Following target innervation, developing and neonatal retinal ganglion cells (RGCs) depend on neurotrophic factors from their target tissue for survival. This dependence is reduced for adult RGCs which rely primarily on trophic support from their local environment; however, some findings indicate that target tissue may play a role in the long-term survival of RGCs. We propose that a deficiency in neurotrophic factors from the target tissue may influence the survival of RGCs when local neurotrophic support is disrupted. Furthermore, we propose that this hypothesis may explain, at least in part, the progressive loss of RGCs in optic neuropathies such as glaucoma. Neurotrophic factors are present in the adult superior colliculus and they are trafficked to the retina; however, removal or lesioning of the adult target tissue results in little or no RGC loss for up to several months. In vitro, adult RGCs will survive when maintained by co-culturing these neurons with their target tissue. As well, the timing and pattern of adult RGC loss is consistent with that seen in glaucoma and in reports of delayed RGC loss following target-removal. Our hypothesis can be tested by selectively disrupting local neurotrophic support and evaluating RGC survival when target-derived neurotrophic support is maintained and when it is disrupted. Specifically, intravitreal injection of blocking antibodies could be used to disrupt local neurotrophic signaling, while aspiration of the superior colliculus will eliminate retrograde transport from the primary target tissue in rodents. The results of these experiments would provide valuable information concerning the influence of target-derived neurotrophic support when local neurotrophin signaling is disrupted. Specifically, this research could verify whether deficiencies in target-derived neurotrophic support play a role in RGC loss during glaucoma. A further understanding of this mechanism may lead to the development of effective neuroprotective strategies for treating glaucoma.

Brain & chiasmal herniations into sella after medical treatment of prolactinoma.

BACKGROUND: Dopamine agonists are widely used in the treatment of pituitary prolactinomas. We report a case of inferior mesial frontal lobe (gyrus rectus) and chiasmal herniations into an enlarged sella following successful medical treatment of a pituitary macroadenoma. METHOD: A 71-year-old healthy man presented to medical attention with visual complaints. On examination, he was found to have bitemporal hemianopsia. Endocrine evaluation revealed an elevated prolactin level. He was treated medically with a dopamine agonist (bromocriptine). RESULTS: Evaluation after one year of medical treatment revealed stabilization of the patient's vision, with a significant bitemporal field loss. Serum prolactin levels normalized (5.16 ng/ml). The MRI of the sella showed almost complete disappearance of the tumor, resulting in right mesial frontal lobe herniation inferiorly into an enlarged sella with associated chiasmal deformation. CONCLUSIONS: We report a case where successful medical treatment of a large pituitary prolactinoma has resulted in inferior frontal lobe and chiasmal herniatons into an enlarged sella.

The role of heat shock proteins Hsp70 and Hsp27 in cellular protection of the central nervous system.

Heat shock proteins (Hsps) are highly conserved and under physiological conditions act as molecular chaperones and/or have anti-apoptotic activities. Expression in the brain of two heat shock proteins, the70 kDa Hsp (Hsp70) and the 27 kDa Hsp (Hsp27), is notable because both proteins are highly inducible in glial cells and neurons following a wide range of noxious stimuli including ischemia, epileptic seizure and hyperthermia. In the central nervous system, constitutive expression of Hsp27 is limited to many (but not all) sensory and motor neurons of the brain stem and spinal cord, while there is little or no constitutive expression of Hsp70. However, inducible expression of both Hsp70 and Hsp27 is present in many areas of the brain and retina and is associated with cellular resistance to a variety of insults. The potential for manipulating the expression levels of Hsps for therapeutic advantage in neurodegenerative diseases such as Alzheimer's disease, stroke and glaucoma will be explored.

Dietary exposure estimates of isoflavones from the 1998 UK Total Diet Study.

The phyto-oestrogen contents of the 1998 UK Total Diet Study (TDS) food group composites were determined. Each TDS set consisted of composite samples, one for each of the 20 designated food groups. These composites then represented the average consumption of all the individual food elements in each group, processed into the form in which they were consumed. In the TDS, individual composites of the bread, processed meat and fish food groups contained >5 mg kg(-1) of the individual isoflavones (daidzein, genistein and glycitein). Individual composites from the groups, miscellaneous cereals, other vegetables, fruit products and nuts contained >1 mg kg(-1). After weighting for average consumption of food from each TDS food group, an estimated daily intake of 3 mg day(-1) of combined isoflavone aglycones was obtained from the TDS sample collection model for the average (adult) consumer. The UK dietary intake of phyto-oestrogens is higher than previously estimated due in part to the use of soya in processed foods.

Determination of unusual soya and non-soya phytoestrogen sources in beer, fish products and other foods.

Fish and fish products (14 samples), Indian foods and meals (10 samples), spices (30 samples) and beers (10 samples) were analysed for their phytoestrogen content, and a number of significant non-soya sources of dietary phytoestrogens were identified. No isoflavones were detected in unprocessed, farmed or ocean fish, but some samples of processed fish products contained soya isoflavones, which are assumed to come from coatings or protein addition. Additionally, some processed fish products contained, genistein glycocongugates not derived from soya. Genistein was detected in Indian meals such that, for example, a single portion of a vindalooo curry contained 11 mg genistein. The origin was most likely from the spices used, since the analysis of curry powders, chilli powder, crushed red chillies, garam masala and tandoori powder revealed that some contained genistein at more than 100 mg kg(-1). Cumin was the most likely source material, although not all individual samples of cumin tested contained high levels of genistein. Prenylnaringenin phytoestrogens were determined in UK hop-based beers at mean concentrations of 0.21 mg(-1) 6-prenylnaringenin and 0.06mg(-1) 8-prenylnaringenin. The beers also contained traces of daidzein, genistein and biochanin A. The significance of 'hidden soya' in processed foods and these non-soya sources of phytoestrogens is that UK dietary intake of phytoestrogens must be assumed to be higher than estimated previously and that some sources of phytoestrogens remain poorly characterized.

Administration of brain-derived neurotrophic factor suppresses the expression of heat shock protein 27 in rat retinal ganglion cells following axotomy.

Optic nerve transection results in the apoptotic cell death of the majority of retinal ganglion cells by 14 days. The neurotrophin brain-derived neurotrophic factor (BDNF) enhances survival of retinal ganglion cells. In addition, the small heat shock protein Hsp27, with its anti-apoptotic effects, may be important for neuron survival following axotomy or trophic factor withdrawal. We recently reported the induction and expression of Hsp27 in a subset of retinal ganglion cells following axotomy. Here we have examined the effect of BDNF administration on the expression of Hsp27 in axotomized adult rodent retinal ganglion cells. Retinal ganglion cells were pre-labeled with Fluorogold prior to optic nerve transection and concomitant intraocular injection of BDNF or vehicle. Hsp27 immunofluorescence was examined in retinal sections from 4 to 28 days following injury. Consistent with previous survival studies, the number of Fluorogold-labeled retinal ganglion cells declined from 100% at 4 days to approximately 15% by 14 days following axotomy and vehicle injection. In contrast, with BDNF administration, retinal ganglion cell survival was maintained at 100% to 7 days following axotomy. We report that the number of Hsp27-positive injured retinal ganglion cells, as detected by immunohistochemical staining, was decreased by 50% in BDNF-treated retinas, when compared with vehicle-treated controls. This decreased expression of Hsp27 in response to BDNF treatment was seen both at early (4 days) and delayed (14 days) times. BDNF following optic nerve transection significantly reduced the expression of Hsp27 in retinal ganglion cells. These results indicate that BDNF may down-regulate alternate cell survival pathways, including the stress-induced expression of Hsp27, and may help to explain the failure of chronic neurotrophin treatment to maintain long-term retinal ganglion cell survival.

Injury to retinal ganglion cells induces expression of the small heat shock protein Hsp27 in the rat visual system.

Optic nerve transection results in apoptotic cell death of most adult rat retinal ganglion cells that begins at 4 days and leaves few surviving neurons at 14 days post-injury [Berkelaar et al. (1994) J. Neurosci. 14, 4368-4374]. The small heat shock protein Hsp27 has recently been shown to play a role in sensory neuron survival following peripheral nerve axotomy [Lewis et al. (1999) J. Neurosci. 19, 8945-8953]. To investigate the role of Hsp27 in injured CNS sensory neurons, we have studied the induction and cell-specific expression of Hsp27 in rat retinal ganglion cells 1-28 days after optic nerve transection. Immunohistochemical results indicate that Hsp27 is not present at detectable levels in the ganglion cell layer of control (uninjured) or sham-operated control rats. In contrast, Hsp27 is detected in retinal ganglion cells from 4 to 28 days following axotomy. Furthermore, the percentage of surviving retinal ganglion cells that are Hsp27-positive increased over the same time period. Hsp27 is also detected in glial fibrillary acidic protein-positive astrocytes in the optic layer of the superior colliculus from 4 to 28 days after optic nerve transection. These experiments demonstrate that transection of the optic nerve results in the expression of Hsp27 in three distinct regions of the rat visual system: sensory retinal ganglion cells in the eye, glial cells of the optic tract, and astrocytes in the optic layer of the superior colliculus. Hsp27 may be associated with enhanced survival of a subset of retinal ganglion cells, providing evidence of a protective role for Hsp27 in CNS neuronal injury.

Verification of the findings of acrylamide in heated foods.

We report here the first confirmation of the recent Swedish findings of acrylamide in heated foods. The verification exercise used an LC-MS/MS method developed for the purpose as well as an established GCMS method for acrylamide analysis. LC-MS/MS was suitable for the direct determination of acrylamide in aqueous extracts of foods by isotope dilution mass spectrometry (IDMS) using triply deuterated acrylamide. Some food matrices were not suited to the new method and mixed-mode solid-phase extraction (SPE) was used to clean these extracts. The foods tested included UK versions of some of the key food groups analysed in Sweden. Also tested were some foods heated under home-cooking conditions. There was good agreement between the LC-MS/MS results and the GC-MS results and the levels of acrylamide found here were similar to those reported for the corresponding foods analysed in the Swedish study. The analyses confirmed that acrylamide is absent from the raw or boiled foods but present at significant levels in fried, grilled, baked and toasted foods. The highest result was 12000 microg kg(-1) acrylamide in overcooked oil-fried chips.

Meningeal melanocytoma of the planum sphenoidale. Case report and review of the literature.

Meningeal melanocytoma is a rare benign primary melanotic tumor of the meninges, most commonly found in the spinal canal and the posterior fossa. The authors report the 19th published case of a supratentorial meningeal melanocytoma and the first reported case in which the tumor arose from the planum sphenoidale. The patient's presenting symptoms were characteristic of a large bifrontal lesion and included headaches, personality change, lethargy, and urinary and fecal incontinence. Computerized tomography and magnetic resonance imaging studies revealed an extraaxial lesion arising from the planum sphenoidale. The patient underwent successful gross total removal of the tumor without neurological sequelae. Based on the findings shown in this case report, meningeal melanocytoma should be included in the differential diagnosis of extraaxial lesions arising from the area of the planum sphenoidale.

Endovascular treatment of a "blister-like" aneurysm of the internal carotid artery.

BACKGROUND: "Blister-like" aneurysms of the supraclinoid internal carotid artery have recently been recognized as having unique pathological and clinical features. Little is known regarding their optimal treatment modality. METHODS: We report a case of a "blister-like" aneurysm of the internal carotid artery treated with Guglielmi detachable coil (GDC) embolization. CASE REPORT: A 55-year-old man presented with a Hunt & Hess grade II subarachnoid hemorrhage. Computed tomography revealed diffuse subarachnoid blood. Cerebral angiography demonstrated a broad-based bulge on the medial wall of the right distal internal carotid artery. The patient was taken to the operating room and underwent a right pterional craniotomy and wrapping of this unclippable aneurysm. On postoperative day 11, he developed signs of vasospasm, and repeat angiography showed remarkable growth of the aneurysm. The aneurysm was believed to be amenable to endovascular therapy and was treated by GDC embolization. The patient recovered well and remained neurologically intact on follow-up examinations. Repeat cerebral angiography was performed three and nine months following his initial presentation and revealed a significant aneurysm neck remnant. This neck remnant was treated by repeat GDC embolization 13 months following his subarachnoid hemorrhage. CONCLUSIONS: "Blister-like" aneurysms of the internal carotid artery are important to recognize and are difficult to manage using traditional surgical approaches. Early repeated cerebral angiography is indicated and, where appropriate, endovascular therapy should be considered in the management of these patients.

Prolonged administration of NT-4/5 fails to rescue most axotomized retinal ganglion cells in adult rats.

The survival of axotomized RGCs was increased by intravitreal NT-4/5 given by repeated injections or osmotic minipumps, but the effects were less complete than predicted. Compared to a single injection of the neurotrophin on day 0, second injections on days 3 or 7 only sustained an additional 10-20% of the RGCs on day 10. Minipumps augmented RGC survival up to 4-fold (50%) at 2 weeks but most RGCs were lost by 1 month. Thus, specific neurotrophins can rescue many RGCs soon after injury but long-term neuronal survival may require a better understanding of changes in neurotrophin receptors and interactions with other molecules.

Meningeal melanocytoma. Report of a case and a historical comparison.

Meningeal melanocytomas are rare tumors of the central nervous system that are found almost exclusively in the posterior fossa and spinal cord and whose natural history is poorly defined. In this report, the authors review the clinical presentation, radiological appearance, operative findings, and histological features in two cases of meningeal melanocytoma: one cranial and one spinal. Two women, aged 21 and 30 years, were admitted to the hospital 60 years apart: the first because of progressive paraplegia and the second because of slowly progressive hearing loss. The first patient had an extradural tumor that was treated by laminectomy, subtotal resection, and postoperative radiotherapy in 1936. Her symptoms recurred 16 years later and she underwent reoperation of the residual tumor, which was found to have an intradural component. The authors' patient, who presented 60 years later, underwent plain and enhanced computerized tomography and magnetic resonance imaging that demonstrated a large posterior fossa lesion indicative of either an acoustic neuroma or a meningioma. She underwent posterior fossa decompression but only partial excision of the tumor could be accomplished because vigorous bleeding limited the extent of the resection. Surgery was followed by radiotherapy. The residual tumor enlarged despite these measures and required repeated resection 6 months later. At the second operation the tumor was much less vascular, perhaps reflecting the effects of radiotherapy, and was removed almost entirely. The patient died 6 months later from an anticoagulant-related cerebellar hemorrhage. In both cases the lesions were jet black, and histological examination revealed melanin-containing hypercellular tumors with rare mitotic figures. Meningeal melanocytomas are being diagnosed with increased frequency in parallel with improvements in neuroimaging and clarification of histological features. Clinical presentation of patients with these tumors typically occurs in their fifth decade and women are affected twice as often as men. The posterior fossa lesions can mimic acoustic neuromas and meningiomas in location and radiological appearance; however, the internal auditory canal is normal. In the spine, meningeal melanocytomas present with the clinical features of myeloradiculopathy. Diagnosis is made intraoperatively from the gross, jet-black appearance of the tumor and from histological examination. Vascularity, size, and location may render complete resection unfeasible. Because of the tumor's propensity to recur, radiotherapy has been recommended but its role remains to be elucidated.