Publications by authors named "Juan M Bilbao"

27 Publications

  • Page 1 of 1

Diagnostic and prognostic biomarkers of a sellar melanocytic tumor mimicking pituitary adenoma: Case report and literature review.

Pathol Res Pract 2015 Sep 24;211(9):682-7. Epub 2015 Apr 24.

Department of Surgery, Division of Neurosurgery, St. Michael's Hospital, 30 Bond Street, Toronto, Ontario, Canada M5B 1W8.

Primary or metastatic melanocytic tumors in the sellar region are rare and can pose a diagnostic challenge. Here we describe a case of a 74-year-old man who underwent radiological investigations for a transient episode of blurred vision. Based on the clinical and endocrinological findings and MRI results, the patient was assumed to have a clinically non-functioning pituitary macroadenoma, which was followed-up over a 2-year period. He did not have any endocrine symptoms or progressive visual deterioration, and no history of past malignancy, including melanoma. Endocrinological investigation was unremarkable; blood hormone levels were within the normal ranges except for low serum total testosterone and bioavailable testosterone levels without symptoms of hypogonadism. The longitudinal MRI follow-up demonstrated a gradual increase in the size of the tumor over the course of 11 months. For this reason, the patient underwent surgery. Pathologic examination including histology, immunohistochemistry and electron microscopy achieved the correct diagnosis of melanocytic tumor of the sellar region morphologic examination is essential in the diagnosis of melanocytic tumors. Hmb-45 is an important diagnostic biomarker in melanocytic lesions. The use and exploration of miRNA, Ki67 and osteopontin are important in understanding the genesis, progression, and prognosis in treatment of patients with melanocytic tumors.
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http://dx.doi.org/10.1016/j.prp.2015.04.005DOI Listing
September 2015

Differentiating between visual hallucination-free dementia with Lewy bodies and corticobasal syndrome on the basis of neuropsychology and perfusion single-photon emission computed tomography.

Alzheimers Res Ther 2014 5;6(9):71. Epub 2014 Dec 5.

L.C. Campbell Cognitive Neurology Clinic, Sunnybrook Health Sciences Centre, Room A4 42, 2075 Bayview Avenue, Toronto, ON M4N 3M5 Canada ; Department of Medicine (Neurology), Brain Sciences Research Program, Sunnybrook Health Sciences, Centre University of Toronto, Room A4 42, 2075 Bayview Avenue, Toronto, ON M4N 3M5 Canada ; Cognition & Movement Disorders Clinic, Sunnybrook Health Sciences Centre, Room A4 42, 2075 Bayview Avenue, Toronto, ON M4N 3M5 Canada ; Neurogenetics Section, Centre for Addiction and Mental Health, University of Toronto, Room A4 42, 2075 Bayview Avenue, Toronto, ON M4N 3M5 Canada.

Introduction: Dementia with Lewy bodies (DLB) and Corticobasal Syndrome (CBS) are atypical parkinsonian disorders with fronto-subcortical and posterior cognitive dysfunction as common features. While visual hallucinations are a good predictor of Lewy body pathology and are rare in CBS, they are not exhibited in all cases of DLB. Given the clinical overlap between these disorders, neuropsychological and imaging markers may aid in distinguishing these entities.

Methods: Prospectively recruited case-control cohorts of CBS (n =31) and visual hallucination-free DLB (n =30), completed neuropsychological and neuropsychiatric measures as well as brain perfusion single-photon emission computed tomography and structural magnetic resonance imaging (MRI). Perfusion data were available for forty-two controls. Behavioural, perfusion, and cortical volume and thickness measures were compared between the groups to identify features that serve to differentiate them.

Results: The Lewy body with no hallucinations group performed more poorly on measures of episodic memory compared to the corticobasal group, including the delayed and cued recall portions of the California Verbal Learning Test (F (1, 42) =23.1, P <0.001 and F (1, 42) =14.0, P =0.001 respectively) and the delayed visual reproduction of the Wechsler Memory Scale-Revised (F (1, 36) =9.7, P =0.004). The Lewy body group also demonstrated reduced perfusion in the left occipital pole compared to the corticobasal group (F (1,57) =7.4, P =0.009). At autopsy, the Lewy body cases all demonstrated mixed dementia with Lewy bodies, Alzheimer's disease and small vessel arteriosclerosis, while the corticobasal cases demonstrated classical corticobasal degeneration in five, dementia with agyrophilic grains + corticobasal degeneration + cerebral amyloid angiopathy in one, Progressive Supranuclear Palsy in two, and Frontotemporal Lobar Degeneration-Ubiquitin/TAR DNA-binding protein 43 proteinopathy in one. MRI measures were not significantly different between the patient groups.

Conclusions: Reduced perfusion in the left occipital region and worse episodic memory performance may help to distinguish between DLB cases who have never manifested with visual hallucinations and CBS at earlier stages of the disease. Development of reliable neuropsychological and imaging markers that improve diagnostic accuracy will become increasingly important as disease modifying therapies become available.
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http://dx.doi.org/10.1186/s13195-014-0071-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4256921PMC
December 2014

A multicenter study of glucocerebrosidase mutations in dementia with Lewy bodies.

JAMA Neurol 2013 Jun;70(6):727-35

Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, National Human Genome Research Institute, NIH, Bethesda, Maryland, USA.

Importance: While mutations in glucocerebrosidase (GBA1) are associated with an increased risk for Parkinson disease (PD), it is important to establish whether such mutations are also a common risk factor for other Lewy body disorders.

Objective: To establish whether GBA1 mutations are a risk factor for dementia with Lewy bodies (DLB). DESIGN We compared genotype data on patients and controls from 11 centers. Data concerning demographics, age at onset, disease duration, and clinical and pathological features were collected when available. We conducted pooled analyses using logistic regression to investigate GBA1 mutation carrier status as predicting DLB or PD with dementia status, using common control subjects as a reference group. Random-effects meta-analyses were conducted to account for additional heterogeneity.

Setting: Eleven centers from sites around the world performing genotyping.

Participants: Seven hundred twenty-one cases met diagnostic criteria for DLB and 151 had PD with dementia. We compared these cases with 1962 controls from the same centers matched for age, sex, and ethnicity.

Main Outcome Measures: Frequency of GBA1 mutations in cases and controls. RESULTS We found a significant association between GBA1 mutation carrier status and DLB, with an odds ratio of 8.28 (95% CI, 4.78-14.88). The odds ratio for PD with dementia was 6.48 (95% CI, 2.53-15.37). The mean age at diagnosis of DLB was earlier in GBA1 mutation carriers than in noncarriers (63.5 vs 68.9 years; P < .001), with higher disease severity scores.

Conclusions And Relevance: Mutations in GBA1 are a significant risk factor for DLB. GBA1 mutations likely play an even larger role in the genetic etiology of DLB than in PD, providing insight into the role of glucocerebrosidase in Lewy body disease.
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http://dx.doi.org/10.1001/jamaneurol.2013.1925DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3841974PMC
June 2013

Exome sequencing identifies titin mutations causing hereditary myopathy with early respiratory failure (HMERF) in families of diverse ethnic origins.

BMC Neurol 2013 Mar 20;13:29. Epub 2013 Mar 20.

Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.

Background: Hereditary myopathy with early respiratory failure (HMERF) was described in several North European families and recently linked to a titin gene (TTN) mutation. We independently studied HMERF-like diseases with the purpose to identify the cause, refine diagnostic criteria, and estimate the frequency of this disease among myopathy patients of various ethnic origins.

Methods: Whole exome sequencing analysis was carried out in a large U.S. family that included seven members suffering from skeletal muscle weakness and respiratory failure. Subsequent mutation screening was performed in further 45 unrelated probands with similar phenotypes. Studies included muscle strength evaluation, nerve conduction studies and concentric needle EMG, respiratory function test, cardiologic examination, and muscle biopsy.

Results: A novel TTN p.Gly30150Asp mutation was identified in the highly conserved A-band of titin that co-segregated with the disease in the U.S. family. Screening of 45 probands initially diagnosed as myofibrillar myopathy (MFM) but excluded based on molecular screening for the known MFM genes led to the identification of a previously reported TTN p.Cys30071Arg mutation in one patient. This same mutation was also identified in a patient with suspected HMERF. The p.Gly30150Asp and p.Cys30071Arg mutations are localized to a side chain of fibronectin type III element A150 of the 10th C-zone super-repeat of titin.

Conclusions: Missense mutations in TTN are the cause of HMERF in families of diverse origins. A comparison of phenotypic features of HMERF caused by the three known TTN mutations in various populations allowed to emphasize distinct clinical/pathological features that can serve as the basis for diagnosis. The newly identified p.Gly30150Asp and the p.Cys30071Arg mutation are localized to a side chain of fibronectin type III element A150 of the 10th C-zone super-repeat of titin.
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http://dx.doi.org/10.1186/1471-2377-13-29DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3610280PMC
March 2013

Investigation of c9orf72 in 4 neurodegenerative disorders.

Arch Neurol 2012 Dec;69(12):1583-90

OBJECTIVE To estimate the allele frequency of C9orf72 (G4C2) repeats in amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTLD), Alzheimer disease (AD), and Parkinson disease (PD). DESIGN The number of repeats was estimated by a 2-step genotyping strategy. For expansion carriers, we sequenced the repeat flanking regions and obtained APOE genotypes and MAPT H1/H2 haplotypes. SETTING Hospitals specializing in neurodegenerative disorders. SUBJECTS We analyzed 520 patients with FTLD, 389 patients with ALS, 424 patients with AD, 289 patients with PD, 602 controls, 18 families, and 29 patients with PD with the LRRK2 G2019S mutation. MAIN OUTCOME MEASURE The expansion frequency. RESULTS Based on a prior cutoff (>30 repeats), the expansion was detected in 9.3% of patients with ALS, 5.2% of patients with FTLD, and 0.7% of patients with PD but not in controls or patients with AD. It was significantly associated with family history of ALS or FTLD and age at onset of FTLD. Phenotype variation (ALS vs FTLD) was not associated with MAPT, APOE, or variability in the repeat flanking regions. Two patients with PD were carriers of 39 and 32 repeats with questionable pathological significance, since the 39-repeat allele does not segregate with PD. No expansion or intermediate alleles (20-29 repeats) were found among the G2019S carriers and AD cases with TAR DNA-binding protein 43-positive inclusions. Surprisingly, the frequency of the 10-repeat allele was marginally increased in all 4 neurodegenerative diseases compared with controls, indicating the presence of an unknown risk variation in the C9orf72 locus. CONCLUSIONS The C9orf72 expansion is a common cause of ALS and FTLD, but not of AD or PD. Our study raises concern about a reliable cutoff for the pathological repeat number, which is important in the utility of genetic screening.
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http://dx.doi.org/10.1001/archneurol.2012.2016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4005900PMC
December 2012

Pathophysiology of protein aggregation and extended phenotyping in filaminopathy.

Brain 2012 Sep;135(Pt 9):2642-60

Department of Neurology, Neuromuscular Centre Ruhrgebiet, University Hospital Bergmannsheil, Ruhr-University Bochum, 44789 Bochum, Germany.

Mutations in FLNC cause two distinct types of myopathy. Disease associated with mutations in filamin C rod domain leading to expression of a toxic protein presents with progressive proximal muscle weakness and shows focal destructive lesions of polymorphous aggregates containing desmin, myotilin and other proteins in the affected myofibres; these features correspond to the profile of myofibrillar myopathy. The second variant associated with mutations in the actin-binding domain of filamin C is characterized by weakness of distal muscles and morphologically by non-specific myopathic features. A frameshift mutation in the filamin C rod domain causing haploinsufficiency was also found responsible for distal myopathy with some myofibrillar changes but no protein aggregation typical of myofibrillar myopathies. Controversial data accumulating in the literature require re-evaluation and comparative analysis of phenotypes associated with the position of the FLNC mutation and investigation of the underlying disease mechanisms. This is relevant and necessary for the refinement of diagnostic criteria and developing therapeutic approaches. We identified a p.W2710X mutation in families originating from ethnically diverse populations and re-evaluated a family with a p.V930_T933del mutation. Analysis of the expanded database allows us to refine clinical and myopathological characteristics of myofibrillar myopathy caused by mutations in the rod domain of filamin C. Biophysical and biochemical studies indicate that certain pathogenic mutations in FLNC cause protein misfolding, which triggers aggregation of the mutant filamin C protein and subsequently involves several other proteins. Immunofluorescence analyses using markers for the ubiquitin-proteasome system and autophagy reveal that the affected muscle fibres react to protein aggregate formation with a highly increased expression of chaperones and proteins involved in proteasomal protein degradation and autophagy. However, there is a noticeably diminished efficiency of both the ubiquitin-proteasome system and autophagy that impairs the muscle capacity to prevent the formation or mediate the degradation of aggregates. Transfection studies of cultured muscle cells imitate events observed in the patient's affected muscle and therefore provide a helpful model for testing future therapeutic strategies.
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http://dx.doi.org/10.1093/brain/aws200DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3437028PMC
September 2012

Transportin 1 accumulates specifically with FET proteins but no other transportin cargos in FTLD-FUS and is absent in FUS inclusions in ALS with FUS mutations.

Acta Neuropathol 2012 Nov 28;124(5):705-16. Epub 2012 Jul 28.

Institute of Neuropathology, University Hospital Zurich, Switzerland.

Accumulation of the DNA/RNA binding protein fused in sarcoma (FUS) as inclusions in neurons and glia is the pathological hallmark of amyotrophic lateral sclerosis patients with mutations in FUS (ALS-FUS) as well as in several subtypes of frontotemporal lobar degeneration (FTLD-FUS), which are not associated with FUS mutations. Despite some overlap in the phenotype and neuropathology of FTLD-FUS and ALS-FUS, significant differences of potential pathomechanistic relevance were recently identified in the protein composition of inclusions in these conditions. While ALS-FUS showed only accumulation of FUS, inclusions in FTLD-FUS revealed co-accumulation of all members of the FET protein family, that include FUS, Ewing's sarcoma (EWS) and TATA-binding protein-associated factor 15 (TAF15) suggesting a more complex disturbance of transportin-mediated nuclear import of proteins in FTLD-FUS compared to ALS-FUS. To gain more insight into the mechanisms of inclusion body formation, we investigated the role of Transportin 1 (Trn1) as well as 13 additional cargo proteins of Transportin in the spectrum of FUS-opathies by immunohistochemistry and biochemically. FUS-positive inclusions in six ALS-FUS cases including four different mutations did not label for Trn1. In sharp contrast, the FET-positive pathology in all FTLD-FUS subtypes was also strongly labeled for Trn1 and often associated with a reduction in the normal nuclear staining of Trn1 in inclusion bearing cells, while no biochemical changes of Trn1 were detectable in FTLD-FUS. Notably, despite the dramatic changes in the subcellular distribution of Trn1 in FTLD-FUS, alterations of its cargo proteins were restricted to FET proteins and no changes in the normal physiological staining of 13 additional Trn1 targets, such as hnRNPA1, PAPBN1 and Sam68, were observed in FTLD-FUS. These data imply a specific dysfunction in the interaction between Trn1 and FET proteins in the inclusion body formation in FTLD-FUS. Moreover, the absence of Trn1 in ALS-FUS provides further evidence that ALS-FUS and FTLD-FUS have different underlying pathomechanisms.
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http://dx.doi.org/10.1007/s00401-012-1020-6DOI Listing
November 2012

Aspergillosis of the Petrous Apex and Meckel's Cave.

Skull Base 2010 May;20(3):189-92

Division of Neuroradiology, Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.

Cranial cerebral aspergillosis is a rare entity in immunocompetent patients. Invasive disease involving the petrous apex and Meckel's cave has rarely been described. We present a case of localized invasive petrous apical and Meckel's cave disease in an immunocompetent patient who presented with hemicranial neuralgic pain.
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http://dx.doi.org/10.1055/s-0029-1246229DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3037105PMC
May 2010

Intra-familial clinical heterogeneity due to FTLD-U with TDP-43 proteinopathy caused by a novel deletion in progranulin gene (PGRN).

J Alzheimers Dis 2010 ;22(4):1123-33

Department of Neurodegenerative Disorders, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.

Frontotemporal dementia (FTD) is one of the commonest forms of early-onset dementia, accounting for up to 20% of all dementia patients. Recently, it has been shown that mutations in progranulin gene (PGRN) cause many familial cases of FTD. Members of a family affected by FTD spectrum disorders were ascertained in Poland and Canada. Clinical, radiological, molecular, genetic, and pathological studies were performed. A sequencing analysis of PGRN exons 1-13 was performed in the proband. Genotyping of the identified PGRN mutation and pathological analysis was carried out in the proband's brother. The onset of symptoms of FTD in the proband included bradykinesia, apathy, and somnolence followed by changes in personality, cognitive deficits, and psychotic features. The proband's clinical diagnosis was FTD and parkinsonism (FTDP). DNA sequence analysis of PGRN revealed a novel, heterozygous mutation in exon 11 (g.2988_2989delCA, P439_R440fsX6). The mutation introduced a premature stop codon at position 444. The proband's brother with the same mutation had a different course first presenting as progressive non-fluent aphasia, and later evolving symptoms of behavioral variant of FTD. He also developed parkinsonism late in the disease course evolving into corticobasal syndrome. Pathological analysis in the brother revealed Frontotemporal Lobar Degeneration-Ubiquitin (FTLD-U)/TDP-43 positive pathology. The novel PGRN mutation is a disease-causing mutation and is associated with substantial intra-familial clinical heterogeneity. Although presenting features were different, rapid and substantial deterioration in the disease course was observed in both family members.
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http://dx.doi.org/10.3233/JAD-2010-101413DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5045304PMC
May 2011

A 24-year-old male with headaches.

Brain Pathol 2010 Jul;20(4):863-6

A 24-year-old man presented with a ten-day history of severe headache leading to collapse. CT studies showed filling defects involving the anterior, middle and posterior cerebral arteries and evidence of ischemia and infarction. Post-mortem examination revealed multiple cerebral infarcts secondary to an arteritic process composed of multi-nucleated giant cells, lymphocytes and histiocytes in both middle and anterior cerebral arteries and one posterior cerebral artery. Both carotid siphons and one renal artery segment were also involved. Extensive workup and stains for systemic and infectious causes were negative, leading to a diagnosis of atypical giant cell arteritis (GCA). Disseminated GCA involving extracranial arteries and the anterior, middle and posterior cerebral arteries leading to cerebral infarction has not been previously reported. We report this atypical case of disseminated GCA in a young patient with clinical features distinct from classic GCA (temporal arteritis) and discuss the differential diagnosis.
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http://dx.doi.org/10.1111/j.1750-3639.2010.00403.xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8094715PMC
July 2010

Primary choroid plexus papilloma of the cauda equina. A case report.

Can J Neurol Sci 2010 May;37(3):416-8

Division of Neurosurgery and Department of Pathology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.

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http://dx.doi.org/10.1017/s0317167100010386DOI Listing
May 2010

Recurrent PNET with MGMT methylation responds to temozolomide.

Can J Neurol Sci 2009 Sep;36(5):654-7

Divison of Neurology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.

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http://dx.doi.org/10.1017/s0317167100008209DOI Listing
September 2009

Chondromyxoid fibroma of the mastoid facial nerve canal mimicking a facial nerve schwannoma.

Laryngoscope 2009 Jul;119(7):1380-3

Division of Neuroradiology, Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.

Chondromyxoid fibroma of the skull base is a rare entity. Involvement of the temporal bone is particularly rare. We present an unusual case of progressive facial nerve paralysis with imaging and clinical findings most suggestive of a facial nerve schwannoma. The lesion was tubular in appearance, expanded the mastoid facial nerve canal, protruded out of the stylomastoid foramen, and enhanced homogeneously. The only unusual imaging feature was minor calcification within the tumor. Surgery revealed an irregular, cystic lesion. Pathology diagnosed a chondromyxoid fibroma involving the mastoid portion of the facial nerve canal, destroying the facial nerve.
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http://dx.doi.org/10.1002/lary.20486DOI Listing
July 2009

Immunohistochemical investigation of hormone receptors and vascular endothelial growth factor concentration in vestibular schwannoma.

Skull Base 2008 Nov;18(6):377-84

University of Toronto, Otolaryngology-Head and Neck Surgery, Sunnybrook Health Sciences Centre, Toronto, Ontario.

Objectives: To determine if a relationship exists between the presence of estrogen receptors (ER), progesterone receptors (PR), or vascular endothelial growth factor (VEGF) and the size, growth rate, and behavior of vestibular schwannoma tumors.

Design: Nine tumor samples from young female patients with large vestibular schwannoma tumors were preselected because they were presumed to be faster growing, more aggressive tumors. Immunohistochemical staining was performed using monoclonal mouse antibodies to ER, PR, and VEGF.

Results: The mean age of the study sample was 32.3 years, mean tumor size was 3.2 cm, and the average growth rate was 0.4 cm per 2 months. The results of immunohistochemical staining for ER and PR in all nine samples were unequivocally negative. Eight of nine tumor samples stained positive for VEGF, with five demonstrating low intensity and three demonstrating moderate intensity staining.

Conclusions: There is histopathological evidence for the expression of VEGF in vestibular schwannomas but not for ER and PR. Further studies are necessary to determine the role of VEGF and other molecular pathways in the growth of vestibular schwannomas and the application of anti-VEGF therapy as a potential treatment option in the future.
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http://dx.doi.org/10.1055/s-0028-1096198DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2637072PMC
November 2008

Primary intracranial leiomyoma: a case report and literature review.

Virchows Arch 2006 Sep 8;449(3):382-4. Epub 2006 Aug 8.

Department of Pathology, Sunnybrook Health Science Centre, 2075 Bayview Avenue, Room E-419, Toronto, ON, M4N 3M5, Canada.

We report a case of primary intracranial leiomyoma in 29-year-old woman presented with severe headache. The radiology diagnosis was consistent with meningioma. However, histologically, the tumor had the characteristic appearance of benign smooth muscle. This was confirmed by immunohistochemistry and electron microscopy. Benign metastasizing leiomyoma was excluded by thorough imaging. Although rare, leiomyoma should be considered in the differential diagnosis of well-circumscribed intracranial lesion.
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http://dx.doi.org/10.1007/s00428-006-0252-zDOI Listing
September 2006

Increased brain tumor resection using fluorescence image guidance in a preclinical model.

Lasers Surg Med 2004 ;35(3):181-90

Department of Medical Biophysics, Ontario Cancer Institute/University Health Network and University of Toronto, Toronto, Ontario, Canada M5G 2M9.

Background And Objectives: Fluorescence image-guided brain tumor resection is thought to assist neurosurgeons by visualizing those tumor margins that merge imperceptibly into normal brain tissue and, hence, are difficult to identify. We compared resection completeness and residual tumor, determined by histopathology, after white light resection (WLR) using an operating microscope versus additional fluorescence guided resection (FGR).

Study Design/materials And Methods: We employed an intracranial VX2 tumor in a preclinical rabbit model and a fluorescence imaging/spectroscopy system, exciting and detecting the fluorescence of protoporphyrin IX (PpIX) induced endogenously by administering 5-aminolevulinic acid (ALA) at 4 hours before surgery.

Results: Using FGR in addition to WLR significantly increased resection completeness by a factor 1.4 from 68+/-38 to 98+/-3.5%, and decreased the amount of residual tumor post-resection by a factor 16 from 32+/-38 to 2.0+/-3.5% of the initial tumor volume.

Conclusions: Additional FGR increased completeness of resection and enabled more consistent resections between cases.
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http://dx.doi.org/10.1002/lsm.20088DOI Listing
February 2005

Pituitary pathology in Erdheim-Chester disease.

Endocr Pathol 2004 ;15(2):159-66

Department of Laboratory Medicine and Pathobiology, St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1W8, Canada.

Pituitary morphologic changes in patients with Erdheim-Chester disease have not been described in detail. We report here the histologic and immunohistochemical findings in the autopsy obtained pituitary of a 35-yr-old woman with extensively disseminated Erdheim-Chester disease. The posterior lobe was completely replaced by xanthogranulomatous infiltrates, providing an explanation for the patient's diabetes insipidus. The anterior lobe was intact and immunohistochemistry demonstrated expression of GH, TSH, FSH, LH, and alpha subunit within the normal range. A clinically observed decrease of anterior pituitary function was interpreted as hypothalamic in origin due to massive destruction of the hypophysial stalk and compression of the hypothalamus. Prolactin immunoreactive cells were numerous, consistent with the view that prolactin cell hyperplasia resulted from the loss of hypothalamic dopaminergic inhibition. Massive Crooke's hyalinization in the ACTH-producing cells was considered unrelated to Erdheim-Chester disease and was the consequence of treatment with pharmacologic doses of glucocorticoid hormones. It can be concluded that prolactin cell hyperplasia may be the only finding in the adenohypophysis of patients with disseminated Erdheim-Chester disease. It appears that in our patient the clinically apparent anterior hypopituitarism was not due to the lack of storage but rather to insufficient release of adenohypophysial hormones caused by the defect in hypothalamic regulation.
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http://dx.doi.org/10.1385/ep:15:2:159DOI Listing
February 2005

Bony metastases of anaplastic oligodendroglioma respond to temozolomide.

Can J Neurol Sci 2004 Feb;31(1):102-8

Division of Neurology, Crolla Family Brain Tumour Research Unit, Sunnybrook and Women's College Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.

Background: Fewer than 30 cases of oligodendroglioma or anaplastic oligodendroglioma metastatic to bone are reported in the literature. Prolonged survival even with therapy is uncommon.

Methods: We report a case of anaplastic oligodendroglioma metastatic to bone with a dramatic and durable response to temozolomide therapy. A retrospective case review, molecular analysis, and literature search were performed.

Results: The patient presented with a right frontal mass in 1990. Progression led to resection of the lesion in 1995. Histology revealed an anaplastic oligodendroglioma and the tumour was found to have allelic loss of heterozygosity (LOH) of chromosome 1p (1p-). He received standard radiation therapy. In 2000 he developed hip and pelvic pain. A bone scan showed multiple skeletal lesions. Magnetic resonance imaging of the brain showed stability of intracranial disease. Resection of one lesion found metastatic anaplastic oligodendroglioma with identical morphology to the patient's original tumour, including glial fibrillary acidic protein expression. The patient was started on standard temozolomide chemotherapy and celecoxib with prompt pain relief, and rapid normalization of serum alkaline phosphatase. He received a total of 12 cycles of combined therapy with no toxicity and no evidence of progression until increasing pain marked disease recurrence. The patient underwent palliative chemo- and radiation therapy but eventually succumbed.

Discussion: Loss of heterozygosity 1p- is associated with prolonged survival in anaplastic oligodendroglioma and may increase the cumulative risk for development of systemic metastases. We speculate that metastases from oligodendroglioma harbouring loss of heterozygosity at chromosome 1p- retain the chemosensitivity of the initial lesion.
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http://dx.doi.org/10.1017/s0317167100002912DOI Listing
February 2004

Usefulness of contrast kinetics for predicting and monitoring tissue changes in muscle following thermal therapy in long survival studies.

J Magn Reson Imaging 2004 Mar;19(3):329-41

Department of Medical Biophysics, University of Toronto, Sunnybrook and Women's College Health Sciences Center, Toronto, Canada.

Purpose: To investigate Gd-DTPA kinetics as indicators of subacute and subchronic histopathological changes following focused ultrasound (FUS) thermal therapy for improved evaluation.

Materials And Methods: A total of 18 FUS lesions were created in the thigh muscle of five rabbits under magnetic resonance (MR) guidance at 1.5 Tesla. The rabbits were killed at different times: 40 hours, three days, and seven days. All lesions were analyzed histologically. An analysis of the uptake kinetics of Gd-DTPA, injected within two hours postheating and before sacrifice, was performed. The resulting kinetic maps, permeability (K(trans)) and leakage space (v(e)), were correlated to T(2)-weighted MR and histology.

Results: Images of K(trans) and v(e) better differentiate subacute and subchronic changes not visible on conventional MR in the days following therapy and are consistent with the histopathology observed. In particular, the border between nonviable and viable tissue is well demarcated. The extent of damage is best indicated on v(e), whereas the borders of inflammation are shown on K(trans). The total lesion extent is relatively stable over the 7 days posttherapy and can be predicted by v(e) or T(2)-weighted MR at early times after heating.

Conclusion: Our results suggest that Gd-DTPA kinetics can complement conventional MR for improved evaluation of FUS thermal therapy by providing finer differentiation of necrotic states, inflammation, and repair processes.
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http://dx.doi.org/10.1002/jmri.20014DOI Listing
March 2004

Prediction of subtle thermal histopathological change using a novel analysis of Gd-DTPA kinetics.

J Magn Reson Imaging 2003 Nov;18(5):585-98

Department of Medical Biophysics, University of Toronto, Toronto, Canada.

Purpose: To investigate Gd-DTPA kinetics as predictors of histopathological changes following focused ultrasound (FUS) thermal ablation for improved planning and assessment.

Materials And Methods: Twenty-nine FUS lesions were created in the thigh muscle of eight rabbits under MR-guidance at 1.5 Tesla. Three rabbits were killed at four hours; and 11 lesions were analyzed with histopathology. Temperature-sensitive MRI using proton-resonant frequency-shift was used for time-dependent temperature measurements. Analysis of the uptake kinetics of Gd-DTPA was performed after Gd-DTPA injection, within 20 minutes after heating and again at two hours after heating. The resulting kinetic maps, permeability (K(trans)) and leakage space (v(e)), were correlated to peak temperatures, T(2)-weighted MR, and histopathology.

Results: Images of K(trans) and v(e) reveal regions of histopathological change not visible on conventional post-therapy MR. At early times after heating, v(e) predicts the area of injury more accurately than T(2) (7 +/- 2% vs. 25 +/- 6% underestimation). A circular region of extensive structural/vascular disruption is indicated only on K(trans) maps. The sharp decrease in K(trans) at the boundary of this region occurs at 47.5 +/- 0.5 degrees C, and may be a better estimate of cell death than the conventional method of temperature threshold (55 degrees C for coagulation) used in therapy planning.

Conclusion: Our results suggest Gd-DTPA kinetics can predict different histopathological changes following FUS ablation and may be valuable for early prediction.
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http://dx.doi.org/10.1002/jmri.10388DOI Listing
November 2003

Solitary fibrous tumor of the orbit.

J Craniofac Surg 2002 Sep;13(5):641-4

Craniofacial Surgery Program, Sunnybrook Health Sciences Center, Toronto, Canada.

Painless unilateral proptosis is a frequent manifestation of numerous orbital neoplastic and non-neoplastic processes. Various mesenchymal tumors of both fibrohistiocytic and vascular origin are well-described causes. Solitary fibrous tumors (SFTs) are rare spindle-cell neoplasms usually found associated with serosal surfaces, especially the pleura, but they have recently been described in a number of extrapleural sites including the orbit. The authors describe the case of an 18-year-old man who presented with a 6-month history of painless proptosis in the right eye. A visible nontender mass in the right supermedial orbit producing ptosis of the upper lid was present. Magnetic resonance imaging (MRI) showed a well-circumscribed soft tissue mass located above the right globe with no obvious invasion of adjacent orbital structures. Uneventful surgical excision through a right frontal-orbitotomy approach was performed. Histological evaluation showed a solid, highly vascular tumor mass composed of spindle cells arranged in short ill-defined fascicles. Intense immunohistochemistry staining for CD34 and B-cell lymphoma 2 (BCL-2) differentiated the lesion from the more common hemangiopericytoma. Though considered benign, local recurrence and extraorbital extension of orbital SFTs have been described. Malignant behavior, including distant metastases, has been documented in as many as 20% of pleural cases with mortality rates as high as 50%. The natural history of this tumor in the orbit is unclear. The authors report the 35th case of orbital solitary fibrous tumor and discuss the differential diagnosis, histopathology, radiological features, and clinical course.
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http://dx.doi.org/10.1097/00001665-200209000-00009DOI Listing
September 2002

Clasmatodendrosis correlating with periventricular hyperintensity in mixed dementia.

Ann Neurol 2002 Sep;52(3):378-81

Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario, Canada.

We report a 79-year-old woman with possible Alzheimer's disease and confluent periventricular white matter hyperintensities on magnetic resonance imaging in whom postmortem analysis unexpectedly demonstrated no periventricular demyelination or cerebral arteriosclerosis. However, astrocytes in the periventricular white matter exhibited clasmatodendrosis, defined as cytoplasmic swelling and vacuolation of astroglia, with beading of their dendrites. This finding represents a previously unrecognized correlate of periventricular white matter hyperintensities. Ann Neurol 2002;52:378-381
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http://dx.doi.org/10.1002/ana.10310DOI Listing
September 2002

Xanthomatous Hypophysitis: A Novel Entity of Obscure Etiology.

Endocr Pathol 1999 ;10(3):237-241

MD, FRCPC.

We report a case of xanthomatous hypophysitis, a recently described entity of obscure etiology affecting the pituitary gland, in a 43-yr-old woman, Histologically it is characterized by infiltration of the anterior pituitary by foamy histiocytes which are strongly immunoreactive for CD68 (histiocytic marker) and are immunonegative for 5100 and CD 1 a. Electron microscopy revealed histiocytes with abundant cytopasmic lipid droplets and membrane bound vacuoles. Fragments of intact anterior pituitary with preserved vascw lar and reticulin networks are seen. Xanthomatous hypophysitis resembles neoplasm on clinical and radiologic grounds.
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http://dx.doi.org/10.1007/BF02738885DOI Listing
January 1999

November 2001: 67-year-old man in coma requiring prolonged mechanical ventilation.

Brain Pathol 2002 Apr;12(2):265-6, 269

University of Toronto Neuropathology, St. Michael's Hospital, Ontario, Canada.

A 67-year-old man was found to have massive pituitary necrosis occupying approximately 85% of the anterior lobe after being supported with mechanical ventilation for 35 days. The findings were compatible with "respirator pituitary" found in mechanically ventilated patients. The lesions represent coagulative infarctions due to ischemia. The role of the respirator is believed to be buying time to allow the changes to develop.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8095813PMC
April 2002

Hypothalamic neurocytoma with vasopressin immunoreactivity: Immunohistochemical and ultrastructural observations.

Endocr Pathol 1992 Jun;3(2):99-104

Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.

Hypothalamic tumors of neuronal derivation are rare. We describe the case of a 55-year-old woman with visual disturbances who was found by magnetic resonance imaging (MRI) to have a sellar and suprasellar tumor. She underwent subtotal surgical resection by a transsphe-noidal approach. By light microscopy the tumor displayed a uniform population of short spindle cells with round to oval nuclei, separated by an abundant fibrillary stroma containing axonal processes as shown by the Bodian stain. The neoplastic cells were immunoreactive for neuron-specific enolase (NSE), synaptophysin, and vasopressin, and nonimmunoreactive for glial fibrillary acidic protein (GFAP), vasoactive intestinal peptide (VIP), bombesin, chromogranin, neurofilament, cytokeratins (high and low molecular weight), vimentin, S100 protein, somatostatin, β-endorphin, galactosamine, growth hormone-releasing hormone (GRH), neurophysin, serotonin, adrenaline and noradrenaline, and corticotropin-releasing hormone (CRH). Ultrastructural features included an abundance of neurosecretory granules within neurites and perinuclear cytoplasm. Synapses and glial stroma were not demonstrable. The term hypothalamic neurocytoma delineates this neuronal tumor with distinctive histologic, immunohistochemical, and ultrastructural features. The identification of vasopressin within the tumor provides evidence of neuroendocrine function.
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http://dx.doi.org/10.1007/BF02921349DOI Listing
June 1992

Multiple myeloma presenting as a sellar plasmacytoma and mimicking a pituitary tumor: Report of a case and a review of the literature.

Endocr Pathol 1990 Dec;1(4):245-248

Department of Pathology, St. Michael's Hospital, Universit of Toronto, Toronto, Ontario, Canada.

A case of multiple myeloma presenting as a plasmacytoma and mimicking a pituitary tumor is reported. The importance of recognizing the existence of plasmacytoma in the differential diagnosis of sellar and parasellar tumors is stressed, as it leads to important differences in management. The literature is reviewed. Patients presenting with plasmacytoma with symptoms of a pituitary adenoma have an average age of 58 years; the male to female ratio is 3:1; diplopia, headache, and progressive visual loss are the most important symptoms; third, sixth, and fourth cranial nerve palsies are the most common signs; and pituitary function is usually normal. CT scan of the sellar region is the imaging modality of choice; pathologically, light and electron microscopy are invaluable in making the correct diagnosis. Making the correct diagnosis allows further appropriate investigation for systemic disease and consequent management.
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http://dx.doi.org/10.1007/BF02915418DOI Listing
December 1990
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