Innocent Until Proven Guilty

Clinical-Pathological Case Study Section Editors: Neil R. Miller, MD Janet Rucker, MD Innocent Until Proven Guilty Heather E. Moss, MD, PhD, Tiffani S. Stroup, DO, Amy Y. Lin, MD, Oliver W. Graf, MD, Aaron M. Halfpenny, DO, Howard L. Lipton, MD, Ari M. Blitz, MD, Tibor Valyi-Nagy, MD, PhD Dr. Moss: A 31-year-old man experienced right eye blurring associated with pain. Magnetic resonance imaging (MRI) of the orbits showed thickening and enhancement of the right optic nerve extending from the globe to just anterior to the chiasm. The patient was given 2 doses of intravenous (IV) corticosteroids for presumed optic neuritis. Nine days later, the patient developed headache and worsening vision, became confused, and was readmitted to hospital. Visual acuity was no light perception (NLP), right eye and 20/20, left eye, with a nasal field deficit. There was bilateral optic disc elevation without hemorrhages or cotton-wool spots. He had receptive aphasia and rightsided weakness. Brain computed tomography (CT) revealed a left temporo-parietal hypodensity with mass effect believed to represent infarction. Two days later, he developed low-grade fever, flaccid paraplegia, and a T4 sensory level. Antibiotics were started for presumed infectious transverse myelitis. Three days later, he became lethargic. CT showed a new petechial hemorrhage in the left hemispheric lesion. He was transferred to our institution for further care. We performed a repeat MRI of the orbits, brain and spine as well as MR spectroscopy and a four-vessel cerebral angiogram. Dr. Blitz: MRI of the orbits shows extensive enlargement and enhancement of the right optic nerve (Fig. 1A). MRI of the brain shows a left temporo-parietal lesion with patchy enhancement, focal diffusion restriction, mass effect, and Departments of Ophthalmology and Visual Sciences (HEM, AYL) and Neurology and Rehabilitation (HEM, HLL), University of Illinois at Chicago, Chicago, Illinois; Department of Neurology (TS), University of Chicago, Chicago, Illinois; Departments of Pathology (AYL, OG, AH, TV-N) and Microbiology and Immunology (HLL), University of Illinois at Chicago, Chicago, Illinois; and Department of Radiology and Radiological Sciences (AMB), Johns Hopkins Medical Center, Baltimore, Maryland. Supported by K12 EY 021475 (H.E.M.), K23 EY 024345 (H.E.M.), Departmental Grant from Research to Prevent Blindness (H.E.M., A.Y.L.), NIH R01 NS077755 (H.L.L.), National Multiple Sclerosis Society (H.L.L.), Modestus Bauer Foundation (H.L.L.). The authors report no conflicts of interest. Address correspondence to Heather E. Moss, MD, PhD, UIC Ophthalmology (MC 648), 1855 W Taylor Street, Chicago, IL 60612; E-mail: [e-mail] 92 hemorrhage (Fig. 1B). MRI of the spine reveals multiple, nonenhancing, longitudinally extensive, cervical, and midto-upper thoracic spinal cord lesions (Fig. 1C). Perfusion images (not shown) demonstrate increased tissue transit time and decreased relative cerebral blood volume in the hemispheric lesion. MR spectroscopy showed elevated lipid/ lactate peak, increased choline peak, and decreased N-acetylasparate peak. Four-vessel cerebral angiography revealed no vascular abnormalities. Overall, the findings are most suggestive of an ischemic or necrotic process, perhaps representing an infectious or inflammatory encephalomyelitis. Dr. Moss: Extensive serological testing was unrevealing (Table 1). He was treated with IV methylprednisolone and plasma exchange followed by an oral steroid taper for presumed hemorrhagic leukoencephalitis (1). Visual acuity in the right eye improved to counting fingers (CF). Cerebrospinal fluid (CSF) analysis 30 days after treatment showed a lymphocyte-predominant pleocytosis and elevated protein (Table 1). Two months after presentation, the patient lost vision in the left eye to NLP. Right eye vision remained CF. Neurological examination was otherwise unchanged. Another MRI of the brain and spinal cord was performed. Dr. Blitz: The previously seen right optic nerve enhancement has resolved, but there is now diffuse enhancement of the left optic nerve (Fig. 2A), and there are new regions of enhancement in the mid-to-lower thoracic spinal cord (Fig. 2B), likely, at least in part, reflecting new enhancing lesions rather than development of enhancement in the regions of pathology previously seen. The left cerebral hemispheric lesion persists and is unchanged in appearance (not shown). The bilateral sequential optic nerve enhancement and multiple spinal cord lesions separated in time and space suggest an ongoing, acute demyelinating disorder. Tumefactive demyelination can certainly produce mass effect, although the extent of mass effect in this case would be unusual. Likewise, hemorrhage is not a commonly encountered finding in the typical demyelinating disorders but may be encountered in rare forms such as acute hemorrhagic leukoencephalitis. Moss et al: J Neuro-Ophthalmol 2016; 36: 92-97 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical-Pathological Case Study FIG. 1. A. Postcontrast coronal T1 magnetic resonance imaging shows enlargement and enhancement of the right optic nerve (arrow). B. Left temporo-parietal lesion demonstrates slight enhancement with evidence of restricted diffusion along the medial and posterior aspects of the lesion. C. Sagittal T2 images of the cervical and thoracic spinal cord reveal multiple longitudinally extensive and expansive lesions. ADC, apparent diffusion coefficient map; DWI, diffusion weighted image; FLAIR, fluid-attenuated inversion recovery image. Dr. Moss: Further serum and CSF testing revealed improved but ongoing protein elevation in the CSF but was otherwise unrevealing (Table 1). CT of chest, abdomen, and pelvis did not show any abnormalities. Scrotal ultrasound was normal. Bone marrow biopsy was unrevealing. Accordingly, it was elected to biopsy the spinal cord. Dr. Valyi-Nagy: A spinal cord biopsy at T10 demonstrated small portions of leptomeninges and spinal cord parenchyma with chronic inflammation dominated by macrophages and extensive necrosis and loss of spinal cord parenchyma. Neither a neoplastic nor an infectious process was detected. Special histological stains, immunostains, and electron microscopy (EM) for bacteria, viruses, fungi, and mycobacteria were negative. The findings were consistent with a late subacuteto-early chronic stage of an ischemic process or a necrotizing demyelinating process such as neuromyelitis optica (NMO). The biopsy findings did not favor multiple sclerosis because of the significant necrosis and tissue loss. Dr. Moss: In view of the biopsy findings, the patient was suspected of having NMO and was treated with IV methylprednisolone, Moss et al: J Neuro-Ophthalmol 2016; 36: 92-97 5 cycles of plasma exchange, and cyclophosphamide. Left eye vision subsequently recovered to 20/800; however, right eye vision remained CF. Seven months after presentation, although on prednisone 80 mg daily, the patient's vision declined to light perception, right eye and hand motions, left eye. He received rituximab with improvement in left eye vision to 20/400. Nine months after initial symptoms, while hospitalized with methicillin resistant Staphylococcus aureus bacteremia, his mental status deteriorated and another MRI of the brain was performed. Dr. Blitz: This MRI shows an extensive lesion involving the brainstem and cerebellum with mass effect, patchy enhancement, focal diffusion restriction (not shown), and hemorrhage (Fig. 3). In addition, the corpus callosum demonstrates extensive fluid-attenuated inversion recovery image hyperintensity, and there is now mass effect on the region of the cerebral aqueduct with developing supratentorial hydrocephalus. Dr. Moss: Shortly after undergoing MRI, the patient lost brainstem reflexes and did not recover. After organ donation, an autopsy was performed. 93 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical-Pathological Case Study TABLE 1. Summary of laboratory testing (bold denotes abnormal test result) At Time of Right Eye Vision Loss (0-1 Months After Presentation) At Time of Left Eye Vision Loss (2 Months After Presentation) Serum tests (inflammatory) Anti-aquaporin 4 Ab Complement: C3, C4, CH 50 ANA, anti DS-DNA Anti-RNP, anti-Smith SSA/B Ab Lupus inhibitor Anti-cardiolipin Ab Anti B2 glycoprotein - - - - Anti-aquaporin 4 Ab - - - - - - - SPEP IgG Kappa monoclonal gammopathy ANCA Cryoglobulins Beta-2 microglobulin Serum tests (infectious) HSV I/II PCR EBV IgG +, IgM neg, Ag neg CMV PCR Hepatitis B,C Ab, Ag HIV ab Coxsakie virus Ab Quantiferon TB gold VZV PCR JCV PCR - - - - HSV I/II PCR EBV Ab CMV Ab - - - - - - Lyme Ab Bartonella henselae IgG, IgM Bartonella quintata IgG, IgM HTLV I/II IgG, IgM Cerebrospinal fluid 30 days post treatment 12 wbc 0 rbc Protein 140mg/dL No oligoclonal bands Myelin basic protein 140 ng/dL HSV I/II PCR EBV PCR CMV PCR VZV PCR Cryptococcal Ag Angiotensin converting enzyme - - - - - At time of left eye vision loss 0 wbc 0 rbc Protein 76 mg/dL No oligoclonal bands Myelin basic protein 279 ng/mL HSV I/II PCR EBV PCR CMV PCR VZV PCR Cryptococcal Ag - IgG index 1.64 IgG synthesis rate 28 mg/day JCV PCR Lyme Ab WNV IgG, IgM Other Nasopharyngeal viral PCR Urine histoplasma Ag - - - Serum paraneoplastic panel Ab, antibody; Ag, antigen; ANA, antinuclear antibody; ANCA, antineutrophil cytoplasmic antibodies; anti-DS-DNA, anti-double stranded deoxyribonucleic acid; anti-RNP, antiribonucleoprotein; CMV, cytomegalovirus; EBV, Epstein-Barr virus; HTLV, human T-lymphotropic virus; JCV, JC virus; neg, negative; PCR, polymerase chain reaction; rx, treatment; SSA/B, anti-Sjogren syndrome antibodies; WNV, West Nile virus; VZV, varicella zoster virus. 94 Moss et al: J Neuro-Ophthalmol 2016; 36: 92-97 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical-Pathological Case Study FIG. 2. A. Postcontrast coronal T1 scan reveals enhancement of the left optic nerve (arrow). B. Postcontrast fat-suppressed sagittal T1 scan of the thoracic spinal cord shows patchy enhancement of new cord lesions. Dr. Valyi-Nagy: Examination of the brain revealed cerebral edema with uncal and cerebellar tonsillar herniation. There was a partially cavitated lesion (8 · 7 · 4 cm) with illdefined borders deep in the left cerebral hemisphere involving the temporal, parietal, and occipital lobes. The brainstem and cerebellum were focally softened and distorted. Sectioning of the cerebellum and brainstem revealed an ill-defined, softened lesion extending from the medulla into the midbrain, right thalamus, and right cerebellar hemisphere. The lower spinal cord demonstrated atrophy and discoloration starting in the lower thoracic region. Histopathologic examination of the left parietal lesion showed predominantly chronic changes, including macrophagic infiltrates, gliosis, and focal cavitation (Fig. 4A). Luxol fast blue (LFB)-periodic acid-Schiff (PAS) and neurofilament stains demonstrated significant myelin and axon loss. Glial fibrillary acidic protein (GFAP) staining highlighted extensive gliosis. Special stains for bacterial, fungal, and acid-fast organisms (Gram, GMS, PAS, acid fast bacteria [AFB]) were negative. Immunostains for herpes simplex virus (HSV)-1, HSV-2, and polyomavirus were negative. Acute lesions were detected in the brainstem, cerebellum, and right basal ganglia with extensive, focally necrotizing inflammation (Fig. 4B). Inflammatory infiltrates were primarily composed of neutrophils, but a significant number of CD68-positive macrophages and a smaller number of CD3-positive T-cells also were noted. Only very rare CD20-positive B-cells were detected. There was vascular and perivascular deposition of eosinophilic material. GFAP staining highlighted extensive fragmentation of astrocytic processes in perivascular areas (Fig. 4C). LFB-PAS special staining and neurofilament immunostaining indicated no selective loss of myelin (Fig. 4D). There was a perivascular loss of aquaporin 4 (AQP4) immunoreactivity (Fig. 4E, F). FIG. 3. Postcontrast sagittal T1 (A) FLAIR (B) and axial gradient echo (C) magnetic resonance imaging shows an extensive lesion involving the brainstem and cerebellum with mild enhancement and hemorrhage. FLAIR, fluid-attenuated inversion recovery image. Moss et al: J Neuro-Ophthalmol 2016; 36: 92-97 95 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical-Pathological Case Study FIG. 4. Histopathology of specimens obtained at autopsy. A. Left temporo-parietal lesion shows gliosis and macrophage infiltration (hematoxylin and eosin, · 400). Brainstem, cerebellar, and basal ganglia changes include: B. necrotizing inflammation (hematoxylin and eosin, ·100); C. astrocytic fragmentation (glial acidic fibrillary protein, ·400); D. no loss of myelin (Luxol fast blue, ·200); E. aquaporin 4 immunoreactivity (AQP4, ·400); F. control (AQT4, ·400); G. chronic inflammation in spinal cord (hematoxylin and eosin, ·50); H. optic nerve shows acute and chronic inflammation (hematoxylin and eosin, ·100); and I. marked loss of ganglion cell layer in the retina (hematoxylin and eosin, ·100). AQP4, aquaporin 4. Immunostains for HSV-1, HSV-2, cytomegalovirus, and polyomavirus were negative. Special stains for bacterial, fungal, and acid-fast organisms (Gram, GMS, PAS, AFB) were also negative. EM showed no evidence of viral organisms. Immunofluorescence staining demonstrated perivascular reactivity for C3, C4, and IgG and no specific reactivity for IgM, C1q, kappa, and lambda. Viral, bacterial, and acid-fast cultures taken from the cerebellum postmortem were negative. Histopathologic examination of the spinal cord revealed predominantly chronic lesions, with parenchymal tissue loss associated with cavitation and macrophagic infiltrates. Specifically, sections from the lower spinal cord demonstrated atrophy and extensive multifocal cavitation associated with macrophagic infiltrates in spinal cord parenchyma (Fig. 4G). Acute inflammatory infiltrates also were present in the leptomeninges. Immunohistochemical and special stains demonstrated significant myelin and axon loss in cord parenchyma and extensive gliosis. Special stains for bacterial, fungal, and acid-fast organisms (Gram, GMS, PAS, AFB) were negative. 96 Sections of the left and right eyes and optic nerves demonstrated multifocal, predominantly chronic but focally acute inflammatory infiltrates in the subarachnoid space around atrophic optic nerves (Fig. 4H). Neurofilament and GFAP immunostains and Masson trichrome special staining were indicative of optic nerve atrophy and gliosis. Gram and GMS special stains were negative for bacteria and fungi. There was marked loss of retinal ganglion cells in the retina bilaterally (Fig. 4I). The pathologic findings, including perivascular deposition of IgG, complement, neutrophilic, and eosinophilic infiltrates, extensive tissue necrosis throughout the central nervous system, destruction of perivascular astrocytes, and loss of AQP4 support a pathological diagnosis of NMO. Final Diagnosis Neuromyelitis Optica. Moss et al: J Neuro-Ophthalmol 2016; 36: 92-97 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical-Pathological Case Study Dr. Moss: Clinical categorization of demyelinating diseases is challenging because of overlapping phenotypes and definitions dependent on clinical course. In our patient, a disease along the demyelinating spectrum was the favored diagnosis from the outset, based on nearly concurrent optic neuritis, transverse myelitis, and the hemispheric lesion. The prominent hemorrhagic hemispheric lesion dissuaded us from an initial diagnosis of NMO and led us to favor hemorrhagic leukoencephalitis, a monophasic neuroinflammatory illness (1). When the chronic relapsing nature of the patient's disease became evident, a clinical diagnosis of NMO was made. We attribute the hemispheric lesion to an atypical demyelinating lesion of the type that is increasingly recognized and compatible with NMO (2,3). AQP4IgG seronegative status, as was the case in our patient, does not rule out the diagnosis of NMO, as the sensitivity of commercially available tests is approximately 65% (4). It is not known whether AQP4-IgG was present in the CSF, as has been reported in some seronegative NMO patients (5). Histopathological distinctions are increasingly helpful in distinguishing demyelinating diseases, as demonstrated in our case (6). Ultimately, findings of perivascular loss of AQP4, perivascular fragmentation of astrocytic processes, and lack of selective myelin loss on postmortem histopathology of the hyperacute cerebellar lesion confirmed the diagnosis of NMO (2,7). Our case provides insight into the mechanism of tissue injury in NMO, including the relative timing of astrocytic injury vs demyelination due to oligodendrocyte injury, which remains incompletely understood (2,8). AQP4-IgG, a serum autoantibody targeting the water channel AQP4, binds at or near the blood-brain barrier and is an important feature of NMO pathogenesis (9,10). Astrocytic foot processes containing AQP4 are believed to be the primary targets of the immune system attack in NMO. Therefore, NMO may represent a demyelinating disease characterized pathologically by demyelination that is secondary to acute destruction of perivascular astrocytes. Histopathological study of acute lesions supports this theory (8,11). Alternatively, it has been proposed that, in a subset of NMO patients, oligodendrocyte apoptosis and selective loss Moss et al: J Neuro-Ophthalmol 2016; 36: 92-97 of minor myelin proteins occurs simultaneously with astrocyte pathology (2). We have presented a fatal case of NMO with a large hyperacute lesion demonstrating extensive astrocytic pathology without significant demyelination. Our findings provide further support for the hypothesis that demyelination in NMO is a secondary event predated by astrocyte injury. REFERENCES 1. Ryan LJ, Bowman R, Zantek ND, Sherr G, Maxwell R, Clark HB, Mair DC. Use of therapeutic plasma exchange in the management of acute hemorrhagic leukoencephalitis: a case report and review of the literature. 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Mult Scler. 2012;18:108-112. 97 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.