Cholesterol accumulates in senile plaques of Alzheimer disease patients and in transgenic APP(SW) mice.

Mounting evidence suggests that cholesterol may contribute to the pathogenesis of Alzheimer disease (AD). We examined whether cholesterol might be present in senile plaques, a hallmark neuropathological feature of AD. We employed 2 different fluorometric-staining techniques (filipin staining and an enzymatic technique) for the determination of cholesterol in brains of postmortem confirmed AD patients and in nondemented, age-matched histopathologically normal controls. AD patient brains showed abnormal accumulation of cholesterol in congophilic/birefringent dense cores of senile plaques that was essentially absent in histopathologically normal controls. To determine whether increased senile plaque-associated cholesterol occurred generally in all plaques or was restricted to a specific subset, quantitative analysis was performed. Data indicate abnormal accumulation of cholesterol in cores of mature plaques but not in diffuse or immature plaques. Additionally, transgenic mice that overexpress the "Swedish" amyloid precursor protein (Tg APP(SW), line 2576) exhibited a similar pattern of abnormal cholesterol accumulation in mature, congophilic amyloid plaques at 24 months of age that was absent in their control littermates or in 8-month-old Tg APP(SW) mice (an age prior to amyloid deposition). Taken together, our results imply a link between cholesterol and AD pathogenesis and suggest that cholesterol plays an important role in the formation and/or progression of senile plaques.

Proximal myotonic myopathy: clinical, neuropathologic, and molecular genetic features.

The primary genetic abnormality in myotonic dystrophy (DM) is an expansion of the CTG trinucleotide repeat on chromosome 19q. Recently, patients with similar clinical features, but without this genetic alteration, have been designated as proximal myotonic myopathy (PROMM). We describe two additional cases of PROMM, both of whom presented with clinical features suggestive of myotonic dystrophy. The patients had electromyographic (EMG) evidence of myotonia, normal cardiac evaluation, and no cataracts. Genetic analysis of peripheral blood leukocytes revealed no expansion of the trinucleotide repeat by polymerase chain reaction (PCR) and Southern blot analysis. Muscle biopsies in both cases were significant with features suggestive of myotonic dystrophy, such as large numbers of fibers containing multiple internal nuclei, occasional nuclear chains, and fiber atrophy, although sarcoplasmic masses and ring fibers were absent. These cases illustrate the clinical and neuropathologic findings of PROMM and underline the importance of correlating these aspects with genetic studies in patients with myotonic muscle disorders.

Pathognomonic MR imaging findings in Balo concentric sclerosis.

Irregular, concentric zones of increased signal on T2-weighted cranial MR imaging studies may strongly suggest Balo concentric sclerosis (BCS), a rare but recognized variant of multiple sclerosis. Differentiating BCS from multiple sclerosis or neoplasm can be difficult clinically, but MR imaging findings noted in this case may be pathognomonic.

Necrotizing sarcoid granulomatosis mimicking an intracranial neoplasm: clinicopathologic features and review of the literature.

We present a unique case of biopsy-proven necrotizing sarcoidosis involving the central nervous system (CNS) in a 52-year-old woman. The patient presented with a 3-month history of left-sided headache and sharp, shooting pains on the left side of her face. She also has a previous history of sarcoidosis, histopathologically confirmed on parotid gland biopsy 24 years before. Imaging studies of the present lesion revealed a 1.8 x 1.4-cm mass in the left temporal lobe with signal intensity suggestive of meningioma or low-grade glial neoplasm. Surgical resection was initiated, and intraoperative consultation with frozen sections revealed granulomata. The lesion was biopsied, and surgical intervention was terminated. Permanent sections failed to reveal bacteria, mycobacteria, fungi, or foreign bodies. A diagnosis of necrotizing neurosarcoidosis was rendered. The patient was administered steroid therapy and clinically responded favorably. At the most recent follow-up almost 2 years later, there was no evidence of recurrence or progression. Necrotizing sarcoidosis has been reported most commonly in the lungs and rarely in other organ systems. We report the first histologically proven case involving the CNS as well as a rare example of sarcoidosis and necrotizing sarcoid granulomatosis in the same patient. Sarcoidosis and its necrotizing variant should be considered in the differential diagnosis of a granulomatous mass lesion involving the CNS, particularly in the context of a history of systemic disease.

Chromosome 17 loss-of-heterozygosity studies in benign and malignant tumors in neurofibromatosis type 1.

Neurofibromatosis type 1 (NF1) is a common autosomal dominant condition characterized by benign tumor (neurofibroma) growth and increased risk of malignancy. Dermal neurofibromas, arising from superficial nerves, are primarily of cosmetic significance, whereas plexiform neurofibromas, typically larger and associated with deeply placed nerves, extend into contiguous tissues and may cause serious functional impairment. Malignant peripheral nerve sheath tumors (MPNSTs) seem to arise from plexiform neurofibromas. The NF1 gene, on chromosome segment 17q11.2, encodes a protein that has tumor suppressor function. Loss of heterozygosity (LOH) for NF1 has been reported in some neurofibromas and NF1 malignancies, but plexiform tumors have been poorly represented. Also, the studies did not always employ the same markers, preventing simple comparison of the frequency and extent of LOH among different tumor types. Our chromosome 17 LOH analysis in a cohort of three tumor types was positive for NF1 allele loss in 2/15 (13%) dermal neurofibromas, 4/10 (40%) plexiform neurofibromas, and 3/5 (60%) MPNSTs. Although the region of loss varied, the p arm (including TP53) was lost only in malignant tumors. The losses in the plexiform tumors all included sequences distal to NF1. No subtle TP53 mutations were found in any tumors. This study also reports the identification of both NF1 "hits" in plexiform tumors, further supporting the tumor suppressor role of the NF1 gene in this tumor type.

CD44 expression and MMP-2 secretion by mouse glioma cells: effect of interferon and anti-CD44 antibody.

We have previously reported that invasiveness of mouse glioma G-26, which expresses CD44 adhesion molecule, was inhibited in vitro following treatment with anti-CD44 antibody or mouse interferon alpha/beta (MuIFN alpha/beta). Here, we evaluated whether the expression of transmembrane CD44 adhesion molecule and/or secretion of extracellular matrix metalloproteinases (MMPs) were affected when glioma cell invasion was inhibited. Flow cytometric evaluation of CD44 adhesion molecule expression in G-26 glioma using anti-CD44 antibody, confirmed that G-26 cells were CD44+. Following 3-day treatment with MuIFN alpha/beta at 8 x 10(2) or 8 x 10(3) IU/ml of glioma cells, the expression of CD44 was not significantly affected as reflected by CD44+ cell number and fluorescence intensity. The pretreatment of glioma cells for 1 day with anti-CD44 antibody resulted in a 30-60% decrease of CD44 expression. This coincided with significantly (p < 0.05) lower cell activity as judged by MTT assay for mitochondrial activity. The zymographic evaluation of MMP activity in the G-26 glioma cell culture showed a high level of the active form of MMP-2. This level of MMP-2 was decreased following 3 day treatment of G-26 glioma cells with either 8 x 10(2) or 8 x 10(3) IU/ml of MuIFN alpha/beta but only the latter concentration produced statistically significant 55% decrease. However, following a 1 day treatment of G-26 glioma cells with anti-CD44 antibody, the level of active MMP-2 form was not significantly affected. These findings indicate that while the inhibitory effect of IFN on glioma invasion was accompanied by a decreased level of the active form of MMP-2 released extracellularly, the expression of the transmembrane CD44 adhesion molecule was not affected. Conversely, anti-CD44 antibody pretreatment of G-26 glioma, which led to the inhibition of glioma invasion, resulted in decreased CD44 expression and lower cell activity but had no effect on the MMP-2.

Chemotherapy for pancreatic cancer: a neuroimaging clinicopathologic correlation.

This 52-year-old male without a significant medical history was receiving chemotherapy with diethylnorspermine (DENSPM), a polyamine analogue, for a partially resected pancreatic adenocarcinoma. Ten months after his initial diagnosis, he was admitted to an outside hospital for evaluation of altered mental status. Over the course of the next few days the patient developed progressive neurologic signs and symptoms including lethargy, tonic deviation of his eyes to the left, asymmetic pupils, and right-sided decerebrate posturing elicited by painful stimuli. Neuroimaging studies revealed multiple lesions scattered in the periventricular white matter, thalamus, midbrain pons, and cerebellar peduncles. The clinical and neuroimaging differential diagnoses are discussed, and postmortem neuropathologic correlation is presented.

Immunohistochemical localization of erythropoietin and its receptor in the developing human brain.

We have previously shown erythropoietin (Epo) and its receptor (Epo-R) to be present in the fetal human central nervous system (CNS), and Epo to be present in the spinal fluid of normal preterm and term infants. To investigate the cellular specificities and developmental patterns of expression of these polypeptides in the human brain-areas that have not been well researched-we designed the following study. Human brains ranging in maturity from 5 weeks post-conception to adult were preserved at the time of elective abortion, surgical removal (tubal pregnancy, or removal for temporal lobe epilepsy), or autopsy. Immunohistochemistry was used to localize Epo and Epo-R reactivity in brains of different stages of development. Astrocytes, neurons, and microglia were identified in sequential tissue sections by specific antibodies. At 5 to 6 weeks post-conception, both Epo and Epo-R localized to cells in the periventricular germinal zone. At 10 weeks post-conception, Epo immunoreactivity was present throughout the cortical wall, with the most intense immunoreactivity present in the ventricular and subventricular zones. Epo-R, in contrast, was localized primarily to the subventricular zone, with little staining evident in the ventricular zone. In late fetal brains, Epo-R reactivity was most prominent in astrocytic cells, although modest reactivity was observed in certain neuron populations. In contrast, Epo staining localized primarily to neurons in fetal brains, although a subpopulation of astrocytes was also immunoreactive. In postnatal brains, both astrocyte and neuron populations were immunoreactive with antibodies to Epo-R and Epo. From these results it is clear that Epo and its receptor are present in the developing human brain as early as 5 weeks post-conception, and each protein shows a specific distribution that changes with development. We speculate that Epo is important in neurodevelopment, and that it also plays a role in brain homeostasis later in life, functioning in an autocrine or paracrine manner.

Retrorectal cyst-hamartomas and sacral dysplasia: MR appearance.

Retrorectal cyst-hamartoma, an uncommon lesion, arises from hindgut embryonic remnants and may be associated with sacral anomalies. Such a lesion is presacral, multicystic, and lined with glandular or transitional epithelium. Malignant transformation of these lesions has been reported. We describe the clinical, pathologic, and imaging findings in an infant.

Neuropathologic applications of immunohistochemical fiber typing in the non-neoplastic muscle biopsy.

The determination of fiber types is routinely accomplished in skeletal muscle biopsy specimens by enzymatic histochemical analysis, which detects adenosine triphosphatase (ATPase) activity on cryostat sections. This study assesses postmortem antigen degradation, the effects of fixation and processing, and the neuropathologic applications of MY-32, a monoclonal antibody to fast twitch skeletal myosin. Formalin-fixed, paraffin-embedded sections of skeletal muscle biopsy specimens obtained from the quadriceps femoris were immunoreacted with this antibody. Cryostat sections of the same muscle biopsy specimens were examined after brief fixation in either acetone or formalin. Parallel cryostat sections of frozen muscle were also assessed with ATPase preparations at pH 9.4 and 4.3. To evaluate the effect of postmortem interval and autolysis on antigen degradation, skeletal muscle samples obtained at 12 hours postmortem were immunoreacted after 12, 24, or 36 additional hours. These specimens were examined as immunoreacted cryostat sections and compared with parallel sections reacted for ATPase at pH 9.4 and 4.3. Representative sections from each time point were also fixed in formalin, routinely processed, paraffin embedded, and immunoreacted. Selected muscle biopsy specimens with a range of neuropathologic diagnoses, including fiber type grouping, Type II atrophy, and congenital fiber type disproportion, were also assessed for immunoreactivity. Our results indicate that the MY-32 monoclonal antibody specifically reacts with Type II (fast twitch) fibers. Immunoreactivity is most intense in cryostat sections immersion fixed in acetone, but moderately intense, specific immunoreactivity can be clearly identified in formalin-fixed (frozen or paraffin-embedded) tissue obtained even 48 hours after death. Application of this nonenzymatic method for fiber type determinations in the neuropathologic evaluation of skeletal muscle biopsies is presented.

Erythropoietin immunolocalization in renal cell carcinoma.

Erythropoietin (EPO) is a well-recognized hormone that induces erythrocytosis in a wide range of physiologic and pathologic situations in mammals. One of these situations is a paraneoplastic erythrocytosis, which might be seen in association with various neoplasms, including renal cell carcinoma (RCC), hepatoma, and cerebellar hemangioblastoma. Although there have been multiple studies confirming the association between this erythrocytosis and the production of EPO by tumor cells, immunohistochemical detection of EPO in formalin-fixed, paraffin-embedded tissue was not described. We report on the use of microwave antigen retrieval to detect EPO in RCCs in such routinely processed tissues. We selected 19 RCCs received as nephrectomy specimens, fixed in formalin, and routinely processed. These cases were previously diagnosed on the basis of morphologic, immunohistochemical, and clinical features. We examined the immunoreactivity of these specimens with a monoclonal anti-EPO antibody. Fetal (20 wk gestational age) liver served as a positive control. Intense positive immunoreactivity was observed as cytoplasmic, granular staining in fetal hepatocytes. Fourteen RCCs (10 clear cell and 4 tubulopapillary types) demonstrated unequivocal cytoplasmic immunoreactivity. Additionally, two clear cell tumors were only focally positive, whereas three (16%) were negative. EPO immunoreactivity might thus prove to be of value in the diagnosis or confirmation of RCC, particularly in the context of routinely processed material.

Calcified cystic lesions in a patient with epilepsy and progressive dementia.

A 67-year-old woman had intractable epilepsy and developed a progressive dementia with upper motor neuron signs over the last 6 years. Magnetic resonance imaging (MRI) revealed multiple areas of large calcified cysts, which increased in number and size over the last 3 years. Discussion includes the appearance of these lesions radiologically and pathologically, as well as their differential diagnosis and clinical significance, focusing on the increasing detection of these lesions with current imaging techniques.

White matter neuronal heterotopia in temporal lobe epilepsy: a morphometric and immunohistochemical study.

A frequent abnormality in temporal lobes (TL) resected for pharmacoresistant epilepsy is the presence of heterotopic neurons within white matter (WM). We compared heterotopic neuron density in 22 TLs surgically resected from epilepsy patients with TLs from 22 non-neurologic cases obtained at autopsies. Neuronal density was assessed on LFB-PAS-stained and parallel sections immunoreacted for microtubule-associated-protein-2 (MAP-2). The white matter area was outlined by an image analysis system. Neurons, identified by morphologic features, were counted within the marked area. Results are expressed as mean +/- SD neurons/mm2. LFB/PAS sections: Epilepsy cases 4.11 +/- 1.86 Autopsy (normal) 2.35 +/- 0.96; MAP-2 sections: Epilepsy cases 4.08 +/- 1.22, autopsy (normal) 1.68 +/-0.92 (significant at 0.05 level by Wilcoxon's Rank Sums test). The lower number of MAP-2-immunopositive neurons in the control group as compared with the histologically identified group is most likely the result of antigen degradation resulting from an increased postmortem interval. These results indicate that normal TLWM contains a heterotopic population of neurons, and that this neuronal density is significantly higher in epilepsy patients. It is felt that this increased neuronal density is an epiphenomenon rather than the cause of seizures, and may be the result of decreased white matter either secondary to disruption of myelination, or loss of neurons as part of mesial temporal sclerosis.

Primary intracranial germ cell tumors: clinicopathologic review of 32 cases.

Primary intracranial germ cell neoplasms are rare tumors and constitute a heterogeneous group. We have reviewed 32 cases, over a 21-year period, from the University of Florida. The cases include 22 germinomas, 6 mixed germ cell tumors, and 4 teratomas. The clinical presentations in these cases were more closely related to the location of the tumor, that is, pineal or suprasellar, rather than the histologic subtype. Neuroimaging evaluation was useful in distinguishing between germinomas, teratomas, and other mixed germ cell tumors (MGCTs), primarily by evaluation of cystic versus solid lesions (teratoma versus germinoma), contents of cysts (teratoma versus MGCT), and infiltrative nature of the tumors (MGCT), although cytologic-histopathologic confirmation remains necessary. Germinomas responded favorably to radiation therapy with survival periods of over 16 years; MGCTs were treated with combination chemotherapy and radiation, with a markedly poorer prognosis. This study underlines the critical significance of histopathologic evaluation of the tumor in determining therapeutic interventions as well as prognosis.

Composite pleomorphic xanthoastrocytoma and ganglioglioma: report of four cases and review of the literature.

Composite pleomorphic xanthoastrocytoma (PXA)-ganglioglioma (GG) is a rare recently described entity. Only three examples have been documented, one of which showed evidence of malignant transformation. We report an additional four cases and update the literature. With the exception of an 82-year-old man, all patients have been under 30 years of age. The temporal lobe was involved in three cases and cerebellum in another three. Radiologic features were those common to PXA and GG. Histologically, all were "collision tumors" composed of abutting, although spatially distinct, PXA and GG components. In two cases, the second element was only recognized at reexcision or recurrence. Histologic anaplasia, always in the PXA component, was evident as brisk mitotic activity and/or necrosis in five cases. Of the seven patients, one died of disease 17 years after the onset of seizures and after multiple recurrences, the last of which largely resembled glioblastoma. We conclude that the composite PXA-GG is a rare neoplasm that shares many features of its individual components. In addition to its temporal lobe predilection, the cerebellum is frequently affected. As when it occurs in isolation, the PXA component of composite PXA-GG possesses the potential for malignant transformation.

Salivary gland-like tumors of the sellar region.

Herein we present a group of rare tumors of the sella region that have not been previously recognized. Although clinically and radiographically the tumors resemble nonfunctioning pituitary adenomas, their histologic, immunohistochemical, and ultrastructural features differ and indicate a salivary gland origin. The lesions cover a morphologic spectrum that includes cellular pleomorphic adenoma, monomorphic adenoma, oncocytoma, and low-grade adenocarcinoma of the salivary gland. All tumors except the oncocytoma were immunoreactive for cytokeratin and were negative for pituitary hormones and synaptophysin. Ultrastructural characteristics in the cases examined include hypodense stromal material, basal lamina, and tonofilament bundles. The single oncocytoma was packed with mitochondria and lacked membrane-bound secretory granules. DNA ploidy based on image analysis and MIB-1 labeling indices showed diversity within this group of tumors, with labeling indices ranging from 0.06% to 15%. The presumed origin of these rare neoplasms is from salivary gland rests related to the normal pituitary gland. Despite their varied morphology, such tumors are easily confused with pituitary adenoma. Although rare, tumors of salivary gland origin should be considered in the differential diagnosis of unusual adenohypophyseal tumors.

Primary intracerebral malignant fibrous histiocytoma: immunohistochemical findings and etiopathogenetic considerations.

We report a case of malignant fibrous histiocytoma (MFH) arising as a second malignancy in a 13-year-old girl with a previous primitive neuroectodermal tumor of the cerebellum (medulloblastoma). The earlier tumor had been resected and treated with chemotherapy. Because of the age of the patient, no radiation therapy was used. The second neoplasm (an MFH), which presented almost 12 years later, was located within the left frontal region and had discrete meningeal attachment. Histologically, it showed the characteristic storiform pattern and pleomorphism of an MFH and displayed characteristic immunohistochemical reactivity. Careful clinical and radiologic investigation failed to reveal any other neoplasm in the body. This case is unique in that the MFH occurred in a young child after an earlier primary primitive neuroectodermal tumor, although at a distant site, and, importantly, without prior radiation therapy. In this report, we briefly review the literature with an emphasis on immunohistochemistry and histogenesis, raising the possibility that the MFH was induced by chemotherapy.

Glomeruloid vascular structures in glioblastoma multiforme: an immunohistochemical and ultrastructural study.

Microvascular proliferation and glomeruloid vascular structures are important histopathological features of glioblastoma multiforme (GBM). The nature of cells participating in the formation of these structures remains unclear and is the subject of this study. To define these cells better, immunohistochemical markers directed against Factor VIII-related antigen (FVIIIR:Ag), alpha smooth-muscle actin (alpha-SMA), and the lectin Ulex europaeus agglutinin type I (UEA-I) were used. Cells lining the vascular channels and a large number of proliferating abluminal cells participating in glomeruloid vascular structure formation showed positive cytoplasmic staining for FVIIIR:Ag and UEA-I. Abluminal and luminal cells were variably labeled for alpha-SMA. Ultrastructurally, complex aggregates of focally anastomosing capillaries with narrow lumina composed the glomeruloid vascular structure. Endothelial cells were hyperplastic, varied in size and shape, overlapped focally, and contained numerous cytoplasmic filaments. Tight junctions bound together adjacent and overlapping endothelial cells. Weibel-Palade bodies, usually absent from brain microvessels, were present in increased numbers in the newly formed capillaries. Each capillary loop was surrounded by basal lamina encompassing a discontinuous layer of pericytes. This study indicates that glomeruloid vascular structures in GBM are complex aggregates of newly formed microchannels lined with hyperplastic endothelial cells that have an altered morphological phenotype and that these microchannels are supported by basal lamina and pericytes and are devoid of astrocytic end-feet.

Disseminated microsporidiosis especially infecting the brain, heart, and kidneys. Report of a newly recognized pansporoblastic species in two symptomatic AIDS patients.

Microsporidia have emerged as important opportunistic AIDS pathogens of the alimentary, respiratory, and urinary tracts. Although nonhuman mammalian microsporidia infections typically include encephalitis, CNS microsporidiosis has not been reported in patients with AIDS. A 33-year-old white male and an 8-year-old black girl presented with seizures and declining mental status. Central nervous system (CNS) imaging studies revealed small peripherally and diffusely enhancing lesions present for at least 2 and 4 months before death, respectively. Both patients expired despite empirical anti-toxoplasma therapy. Their brains contained innumerable soft gray matter lesions that consisted of central areas of necrosis, filled with free spores and spore-laden macrophages, surrounded by microsporidia-infected astrocytes. The complete autopsy of the child also revealed necrotizing and sclerosing cardiac and renal microsporidiosis and infection of the pancreas, thyroid, parathyroids, liver, spleen, lymph nodes, and bone marrow. Infected cells included astrocytes, cardiac myocytes, epithelium, endothelium, vascular smooth muscle cells, hepatocytes, adipocytes, Schwann cells, and macrophages. Light and electron microscopic studies revealed pansporoblastic development within thick-walled sporophorous vacuoles of parasite origin. Although most similar to Pleistophora sp and Thelohania sp, this microsporidian is different from any known species. Microsporidiosis should be considered as the possible cause of a wide range of diseases in AIDS patients, including CNS, cardiac, and renal.

Extradural myxopapillary ependymoma: report of two cases and review of the literature.

The cauda equina is the most frequent location for ependymomas, particularly the myxopapillary variant, which generally arises from the filum terminale. These tumors have a characteristic histopathologic pattern and are usually easily recognized. The occurrence of these tumors in an extradural, sacrococcygeal, or subcutaneous location may prove challenging, particularly in the absence of any obvious central nervous system connection. We describe two such extradural cases, one with multiple regional and distant metastases and the other with multiple recurrences. The origin of these tumors from subcutaneous sacrococcygeal ependymal rests is postulated on the basis of earlier reports. Clinical and histopathological features are described and a review of the literature is presented.