Reversible paraneoplastic encephalomyelitis associated with a benign ovarian teratoma

Evolution of methods to detect paraneoplastic antibodies

An adaptive immune response in less than 1% of people who develop cancer produces antibodies against neuronal proteins. These antibodies can be associated with paraneoplastic syndromes, and their accurate detection should instigate a search for a specific cancer. Over the years, multiple systems, from indirect immunofluorescence to live cell-based assays, have been developed to identify these antibodies. As the specific antigens were identified, high throughput, multi-antigen substrates such as line blots and ELISAs were developed for clinical laboratories. However, the evolution of assays required to identify antibodies to membrane targets has shone a light on the importance of antigen conformation for antibody detection. This chapter discusses the early antibody assays used to detect antibodies to nuclear and cytosolic targets and how new approaches are required to detect antibodies to membrane targets. The chapter presents recent data that support international recommendations against the sole use of line blots for antibody detection and highlights a new antigen-specific approach that appears promising for the detection of submembrane targets.

Limbic encephalitis in a child with ovarian teratoma and influenza B. Case report and critical review of the history of autoimmune anti-N-methyl-d-aspartate receptor encephalitis

We report the appearance of clinical symptoms and signs of N-methyl-d-Aspartate (NMDA) receptor encephalitis in a patient presenting just days after contraction of influenza B. The offending mature ovarian teratoma was identified and removed on the 10th day after the appearance of symptoms, with subsequent nearly complete resolution of symptoms over the subsequent 6 months. We provide a focused literature review of the clinical and pathophysiologic literature of anti-NMDA receptor encephalitis pertaining to influenza B virus and the pediatric population. Taken together, this study contributes to the pathophysiological understanding of anti-NMDA receptor encephalitis and aids clinicians in its early recognition and management.

Inflammation in Tic Disorders and Obsessive-Compulsive Disorder: Are PANS and PANDAS a Path Forward?

This review and commentary is the product of an invited lecture called "Autoimmunity: PANS/PANDAS" presented at the 2018 Neurobiology of Diseases in Children Symposium in Chicago, IL. The talk addressed clinical and scientific questions and recently published data. At this time, among highly experienced and respected clinicians and researchers spanning relevant disciplines, there is substantial controversy regarding a role for inflammation in producing tics and obsessive-compulsive disorder. This commentary summarizes these controversies, discusses reasons for opposing views on best clinical practices, and concludes with suggestions for pathways forward.

The role of the laboratory in the expanding field of neuroimmunology: Autoantibodies to neural targets

Accelerated identification of autoantibodies associated with previously idiopathic neurological disease has provided insights into disease mechanisms, enhanced understanding of neurological function, and opportunities for improved therapeutic interventions. The role of the laboratory in the expanding field of neuroimmunology is critical as specific autoantibody identification provides guidance to clinicians in diagnosis, prognosis, tumor search strategies, and therapeutic interventions. The number of specific autoantibodies identified continues to increase and newer testing strategies increase efficiencies in the laboratory and availability to clinicians. The need for broadly targeted efficient testing is underscored by the variability in clinical presentation and tumor associations attributable to a specific autoantibody, and conversely the various autoantibody specificities that can be the cause of a given clinical presentation. While many of the antineural antibodies were first recognized in the setting of neoplastic disease, idiopathic autoimmune neurological disease in the absence of underlying tumor is increasingly recognized. Appropriation of therapeutic modalities used to treat autoimmune disease to treat these autoantibody mediated neurological diseases has improved patient outcomes. Interaction between clinicians and laboratorians is critical to our understanding of these diseases and optimization of the clinical benefits of our increasing knowledge in neuroimmunology.

Extra-central nervous system target for assessment and treatment in refractory anti-N-methyl-d-aspartate receptor encephalitis

Anti-N-methyl-d-aspartate-type glutamate receptor autoimmune encephalitis can arise in the setting of ovarian teratoma and often responds to resection. When it occurs in the absence of tumor, failure to respond to treatment may be more likely, and affected patients often require intensive care. To further understand the mechanisms and potential management, we present findings from an autopsy conducted on a young woman who died of refractory autoimmune encephalitis of this type. Rituximab was administered 70 days before death, and both 37 and 14 days before death, CD19⁺ lymphocytes were only 0.1% of blood cells. Ten sessions of plasmapheresis were performed after rituximab treatment. Nonetheless, the autoantibodies were present in serum 4 days before death, demonstrating ongoing antibody production. The hippocampus and medial temporal lobe demonstrated inflammation with T cell and prominent microglial involvement, but no plasma cells or plasmablasts were found there, or anywhere in the brain, despite an extensive search. Examination of lymph node tissue identified many plasma cells along sinusoids. These findings demonstrate that the antibody-producing cells are long-lived and can reside in lymphoid tissue. Awareness of continuing antibody production, the extra-central nervous system site, the indication for cytotoxic therapy, and the potential for biopsy assessment may lead to more effective treatment.

Skew Deviation: Case Report and Review of the Literature

OBJECTIVE

To present a patient with a sudden onset ocular tilt reaction (OTR) and review recent knowledge and evolving insights of the underlying pathophysiological mechanisms of skew deviation and OTR.

METHODS

A middle-aged hypertensive man who had previously suffered stroke with good recovery presented with sudden-onset double vision, slurred speech, ataxia, and a head tilt. Romberg test was positive. The patient denied having disturbances of visual acuity, eye pain, or recent trauma. The right eyeball was pushed upward. The patient complained of double vision in any gaze direction. Movements of the extraocular muscles (EOMs) in the horizontal plane were normal, whereas vertical version and convergence were not possible. We administered a Hess-Lancaster test, cover test, fundoscopic examination, Parks-Bielschowsky three-step test, upright-supine test, brain magnetic resonance imaging (MRI), transcranial doppler (TCD) ultrasonography, electrocardiogram (ECG), Holter monitor (24 h), and echocardiography.

RESULTS

The Hess-Lancaster test showed superior rectus muscle and inferior obliquus muscle palsy to the left and rectus inferior muscle and superior obliquus muscle palsy to the right. The right eyeball fell behind when looking downward and the left eyeball when looking upward. Cover alternating test was positive from vertical, R/L. Examination of the ocular fundus showed incyclotorsion of elevated right eye and excyclotorsion of depressed eye. The Parks-Bielschowsky three-step test was negative. A brain MRI with gadolinium revealed a small zone of diffusion restriction in the medial portion of the right cerebral peduncle and right thalamus. There was a gradual improvement in the patient's neurological status following treatment.

CONCLUSION

Skew deviation, a not uncommon clinical condition, should be promptly recognized when binocular vertical diplopia cannot be interpreted by trochlearis and oculomotor nerve lesion, myasthenia gravis, or orbital pathology. Maddox rod, cover test, Parks-Bielschowsky three-step, and other tests should help to establish the diagnosis. The prognosis depends on etiology, but it is commonly favorable; the majority of patients recover spontaneously after less than a year. More invasive management options should be discussed thereafter.

Severe central and peripheral paraneoplastic demyelination associated with tumours of the ovaries

PURPOSE

The aim of the study is to present MRI examinations of the brain and spinal cord, performed in girls with acute severe neurological presentation of paraneoplastic syndrome associated with ovarian teratomas. Paraneoplastic neurological syndrome (PNS) is a rare disorder caused by remote effects of malignancy in different organs. The pathogenesis of PNS concerns the autoimmune system and specific antibodies. PNS can be seen as encephalomyelitis, limbic encephalitis, progressive multifocal leukoencephalopathy, cerebellar ataxia, brainstem encephalitis, and paraneoplastic cerebellar degeneration. These symptoms are potentially reversible, if the underlying neoplasm is removed.

METHODS

We presented three girls, aged 13, 17, and 18 years. They were all referred to the hospital because of an acute onset of severe disseminated encephalomyelitis. All MRI exams were performed on a 1.5 T scanner with a routine brain and spinal cord protocol, including TSE T2-WI and FLAIR sequences. In all cases, a contrast agent was injected in the standard dose.

RESULTS

Neurological examination performed at the onset of the disease revealed hemiparesis, seizures, and consciousness disturbances. In one girl, visual field loss was also disclosed. They were all healthy before the onset of the disease. Brain and spinal cord MR imaging revealed multiple hyperintense lesions located supratentorially in the white matter of both hemispheres, in the pons, cerebellum, and spinal cord. Patients were treated with methyloprednisolone IV and IVIG. They all improved but significant sequelae were present. Two of them developed symptoms of acute demyelinating polyradiculoneuropathy within 2 months after the onset of encephalomyelitis. At the same time, brain MRI showed progression of the lesions. In two patients, anti-Yo antibodies were present in blood. Extensive examinations revealed bilateral ovarian teratomas in two patients, and left-sided ovarian teratoma in one case. Surgical resection of teratomas resulted in rapid clinical improvement.

CONCLUSIONS

These cases show that in children and adolescents, acute demyelinating disease can be a manifestation of paraneoplastic neurological syndrome. Thus, PNS should always be considered in the differential diagnosis of encephalomyelitis. In female children and adolescents with suspected PNS, it is important to search for ovarian tumours.

Extensive myelitis associated with anti-NMDA receptor antibodies

Background

Encephalitis with anti-N-methyl-D-aspartate receptor antibodies (anti-NMDAR-Ab) is a rapid-onset encephalitis including psychosis, seizures, various movement disorders and autonomic system disturbances.

Case presentation

We report a very unusual case of extensive myelitis associated with anti-NMDAR-Ab. MRI also revealed a hyperintense T2 lesion, non-suggestive of MS, which progressively extended, associated with periventricular gadolinium enhancement visualized on brain MRI. Ophthalmological evaluation showed subclinical right optic neuritis. The absence of anti-AQP4 antibody argued against neuromyelitis optica spectrum disorder. A slight psychomotor slowing prompted us to search for various causes of autoimmune encephalitis. Anti-NMDAR-Ab was found in cerebrospinal fluid.

Conclusion

In patients with extensive myelitis who are seronegative for anti-AQP4 antibodies, and after other classical causes have been excluded, the hypothesis of atypical anti-NMDAR-Ab encephalitis should also be considered.

[N-methyl-d-aspartate receptor antibody encephalitis: a treatable disorder involving B-lymphocytes. A report of two patients]

INTRODUCTION

N-methyl-D-aspartate receptor antibody (anti-NMDA-r AB) encephalitis has been recently identified. We report two cases illustrating the clinical features, response to immunomodulatory treatment and involvement of B-lymphocytes that characterizes this disorder.

CASE REPORTS

These patients illustrated the classic clinical features of anti-NMDA-r AB encephalitis including occurrence in young female, presence of severe neurological and psychiatric manifestations with confusion, seizures, mutism, hypovigilence and involuntary movements, and inflammatory cerebrospinal fluid. Both patients improved after immunotherapy. In case 1, the encephalitis was associated with an ovarian teratoma containing neuronal elements. In case 2, there was no tumor identified. A brain biopsy showed prominent perivascular B-cells infiltrates with some T-cells distributed in the brain parenchyma.

CONCLUSION

Anti-NMDA-r AB encephalitis is certainly not rare and needs to be promptly recognized and treated. An associated neoplasia is inconstant and the pathophysiology involves humoral immunity.

Expanding spectrum of encephalitis with NMDA receptor antibodies in young children

The authors report here 2 cases of subacute-onset encephalitis with N-methyl-D-aspartate (NMDA) receptor antibodies. One had a paraneoplastic syndrome associated with a neuroblastoma, whereas the other had no primary tumor. This disease was originally described as a paraneoplastic syndrome in young women with ovarian teratoma. The clinical features of both children resembled the typical symptoms reported for older patients with this disease: psychomotor deterioration, movement disorders, and seizures. One of the reported cases is the first known case of paraneoplastic encephalitis with NMDA antibodies in a child with neuroblastoma. Both cases described here were younger than any of the previously reported cases. Consistent with recently published series, this report suggests that the spectrum of symptoms of encephalitis with NMDA receptor antibodies is probably wider than previously thought.

A patient with encephalitis associated with NMDA receptor antibodies

BACKGROUND

A 34-year-old woman presented with headache, feverish sensation and anxiety, rapidly followed by homicidal ideation, aggressive agitation, seizures, hypoventilation, hyperthermia and prominent autonomic instability requiring intubation and sedation. She developed episodes of hypotension and bradycardia with periods of asystole lasting up to 15 seconds. Upon weaning off sedation, her eyes opened but she was unresponsive to stimuli. There was muscle rigidity, frequent facial grimacing, rhythmic abdominal contractions, kicking motions of the legs, and intermittent dystonic postures of the right arm.

INVESTIGATIONS

Routine laboratory testing, toxicology screening, studies for autoimmune and infectious etiologies, brain MRI scan, lumbar puncture, electroencephalogram, whole-body CT scan, abdominal ultrasound, paraneoplastic and voltage-gated potassium channel antibody serologies, analysis of N-methyl-D-aspartate receptor antibodies.

DIAGNOSIS

Paraneoplastic encephalitis associated with immature teratoma of the ovary and N-methyl-D-aspartate receptor antibodies.

MANAGEMENT

Intensive care, mechanical ventilation, antiepileptics, laparotomy and left salpingo-oophorectomy, corticosteroids, plasma exchange, intravenous immunoglobulin, cyclophosphamide, physical therapy, and chemotherapy.

Clinical analysis of paraneoplastic encephalitis associated with ovarian teratoma

BACKGROUND

Recently, paraneoplastic encephalitis associated with ovarian teratoma has been described and related to an autoantibody.

METHODS

We describe four patients with ovarian teratoma-associated encephalitis (OTE) and compared their clinical pictures with those of 17 previously reported patients with OTE.

RESULTS

Clinically, OTE was characterized by the development of acute prominent psychiatric symptoms (20 of 21 patients), seizures (15 of 21 patients), and central hypoventilation (13 of 21 patients). Our patients had hypersalivation (three patients) and cardiac conduction problems (all patients); hypothermia was present in one patient. The mean time from the onset of OTE to tumor diagnosis was 19.6+/-22.1 weeks. Ventilatory support was required for 54.9+/-25.4 days on average. The white blood cell count in cerebrospinal fluid was 55.1+/-61.2/mm3. Twelve patients showed abnormalities on cranial MRI, involving areas such as the temporal regions (seven patients) or brainstem (four patients). In addition to tumor resection, 17 patients received some type of immunotherapy: 17 patients received corticosteroids, 10 received intravenous immunoglobulins, two received cyclophosphamide, seven received plasma exchange. Eighteen patients with OTE had neurological improvement, including 11 with full recovery.

CONCLUSIONS

OTE presents with cardiac conduction problems and hypersalivation in addition to psychiatric symptoms, seizures, and central hypoventilation.

Paraneoplastic anti-N-methyl-D-aspartate receptor encephalitis associated with ovarian teratoma

OBJECTIVE

To report the autoantigens of a new category of treatment-responsive paraneoplastic encephalitis.

METHODS

Analysis of clinical features, neuropathological findings, tumors, and serum/cerebrospinal fluid antibodies using rat tissue, neuronal cultures, and HEK293 cells expressing subunits of the N-methyl-D-aspartate receptor (NMDAR).

RESULTS

Twelve women (14-44 years) developed prominent psychiatric symptoms, amnesia, seizures, frequent dyskinesias, autonomic dysfunction, and decreased level of consciousness often requiring ventilatory support. All had serum/cerebrospinal fluid antibodies that predominantly immunolabeled the neuropil of hippocampus/forebrain, in particular the cell surface of hippocampal neurons, and reacted with NR2B (and to a lesser extent NR2A) subunits of the NMDAR. NR2B binds glutamate and forms heteromers (NR1/NR2B or NR1/NR2A/NR2B) that are preferentially expressed in the adult hippocampus/forebrain. Expression of functional heteromers (not single subunits) was required for antibody binding. Eleven patients had teratoma of the ovary (six mature) and one a mature teratoma in the mediastinum; five of five tumors examined contained nervous tissue that strongly expressed NR2 subunits and reacted with patients' antibodies. Tumor resection and immunotherapy resulted in improvement or full recovery of eight of nine patients (paralleled by decreased antibody titers); two of three patients without tumor resection died of neurological deterioration. Autopsies showed extensive microgliosis, rare T-cell infiltrates, and neuronal degeneration predominantly involving, but not restricted to, the hippocampus.

INTERPRETATION

Antibodies to NR2B- and NR2A-containing heteromers of the NMDAR associate with a severe but treatment-responsive encephalitis. Our findings provide a diagnostic test and suggest a model of autoimmune NMDAR-related encephalitis with broad implications for other immune-mediated disorders of memory, behavior, and cognition.

Paraneoplastic neurologic syndromes

Paraneoplastic neurologic disorders (PND) are remote medical complications of cancer that cannot be attributed to direct effects of the neoplasm or its metastases. PND are uncommon, disabling syndromes that have been recognized for more than 50 years. Despite their rarity, these diseases are the subject of intensive research and clinical fascination. This review highlights notable recent publications related to PND. In recent years, the broad clinical spectrum of PND has become even more apparent. PND can affect any part of the central or peripheral nervous system and often affect multiple areas simultaneously. These disorders are often associated with neuron-specific autoantibodies in the serum and cerebrospinal fluid. In clinical practice, detection of these antibodies is crucial for the diagnosis because the neurologic symptoms usually precede the diagnosis of cancer. Recent publications have described new antibody specificities associated with PND and expand our ability to identify patients serologically. Once diagnosed, detection of cancer can be difficult, but the use of positron emission tomography has been shown to be a useful supplement to standard imaging procedures. PND are thought to be autoimmune disorders precipitated by the immune response to cancer. Observations and laboratory studies in PND patients have shown that activation of cytotoxic T cells is an important component of the disease. These studies not only shed light on the pathogenesis of PND and the mechanisms of effective antitumor immunity but may eventually lead to improved treatment.

Paraneoplastic limbic encephalitis caused by ovarian teratoma with autoantibodies to glutamate receptor

We report a rare case of paraneoplastic limbic encephalitis with autoantibodies to glutamate receptor (GluR) in the cerebrospinal fluid (CSF). The 35-year-old woman with consciousness disturbance was diagnosed initially as non-herpetic encephalitis. Her signs and symptoms improved with acyclovir and steroid pulse therapy. However, after the treatment, an ovarian tumor was discovered, and we detected autoantibodies to GluR in the CSF. A possible association between the ovarian teratoma and GluR is suggested.

Accidental seizure with repetitive transcranial magnetic stimulation

Accidental induction of convulsions by using repetitive transcranial magnetic stimulation (rTMS) has been reported to have occurred in 6 normal voluntary subjects, in 1 patient with depression and in 1 patient who had temporal lobe epilepsy, with secondary generalization. In addition, 3 other cases have been published relating its use with seizure induction and in 1 case, using 1-Hz stimulation. In this paper, we report a patient who was participating in a protocol for the use of rTMS in chronic pain, with stimulation in the motor cortex, who developed a generalized seizure in the fifth application. Intertrain interval was within safety guidelines, but the combination of 10 Hz for 10 seconds was excessive and must be considered the main cause for the episode. No further complication has been noted after she was withdrawn from the study protocol.

Managing paraneoplastic neurological disorders

Paraneoplastic neurological syndromes (PNS) are remote effects of cancer that are not caused by invasion of the tumor or its metastases. Immunologic factors appear important in the pathogenesis of PNS because antineuronal autoantibodies and T-cell responses against nervous system antigens have been defined for many of these disorders. The immunologic response is elicited by the ectopic expression of neuronal antigens by the tumor. Expression of these so-called "onconeural" antigens is limited to the tumor and the nervous system and sometimes also the testis. At the time of presentation of the neurological symptoms, most patients have not yet been diagnosed with cancer. Detection of paraneoplastic antibodies is extremely helpful in diagnosing an otherwise unexplained and often rapidly progressive neurological syndrome as paraneoplastic. In addition, the paraneoplastic antibodies may also direct the search for an underlying neoplasm. On the other hand, in patients known to have cancer, the presentation of a PNS may herald recurrence of the tumor or a second tumor. The number of paraneoplastic antibodies is still growing, and at least seven of these can now be considered well characterized. Based on the clinical syndrome, the type of antibody, and the presence or absence of cancer, patients are classified as having a "definite" or "possible" PNS. Despite the presumed autoimmune etiology of PNS, the results of various forms of immunotherapy have been disappointing, with some exceptions. Rapid detection and immediate treatment of the underlying tumor appears to offer the best chance of stabilizing the patient and preventing further neurological deterioration.

EFA6A-like antibodies in paraneoplastic encephalitis associated with immature ovarian teratoma: a case report

We describe a 19-year-old patient with paraneoplastic encephalitis associated with immature ovarian teratoma (OT), who presented with psychiatric symptoms, prolonged disturbance of consciousness, refractory status epilepticus, central hypoventilation, and various abnormal involuntary movements. Immunological characterization of the patient's serum and cerebrospinal fluid (CSF) demonstrated the presence of an autoantibody that colocalized with EFA6A, a brain-specific protein involved in the regulation of dendritic development of hippocampal neurons. Despite the severity of the symptoms, the patient showed significant neurological improvement following removal of the tumor and chemotherapy. This case suggests that physicians should rule out an OT in young women with encephalitis who present with the subacute-onset of psychiatric symptoms. Antibodies that colocalize with EFA6A are a valuable marker for early diagnosis of a potentially reversible paraneoplastic encephalitis associated with OT.

Skew Deviation Revisited

Skew deviation is a vertical misalignment of the eyes caused by damage to prenuclear vestibular input to ocular motor nuclei. The resultant vertical ocular deviation is relatively comitant in nature, and is usually seen in the context of brainstem or cerebellar injury from stroke, multiple sclerosis, or trauma. Skew deviation is usually accompanied by binocular torsion, torticollis, and a tilt in the subjective visual vertical. This constellation of findings has been termed the ocular tilt reaction. In the past two decades, a clinical localizing value for skew deviation has been assigned, and a cogent vestibular mechanism for comitant and incomitant variants of skew deviation has been proposed. Our understanding of skew deviation as a manifestation of central otolithic dysfunction in different planes of three-dimensional space is evolving. The similar spectrum of vertical ocular deviations arising in patients with congenital strabismus may further expand the nosology of skew deviation to include vergence abnormalities caused by the effects of early binocular visual imbalance on the developing visual system.

Paraneoplastic encephalitis, psychiatric symptoms, and hypoventilation in ovarian teratoma

We report four young women who developed acute psychiatric symptoms, seizures, memory deficits, decreased level of consciousness, and central hypoventilation associated with ovarian teratoma (OT) and cerebrospinal fluid (CSF) inflammatory abnormalities. Three patients recovered with treatment of the tumor or immunosuppression and one died of the disorder. Five other OT patients with a similar syndrome and response to treatment have been reported. Our patients' serum or CSF showed immunolabeling of antigens that were expressed at the cytoplasmic membrane of hippocampal neurons and processes and readily accessed by antibodies in live neurons. Immunoprobing of a hippocampal-expression library resulted in the isolation of EFA6A, a protein that interacts with a member of the two-pore-domain potassium channel family and is involved in the regulation of the dendritic development of hippocampal neurons. EFA6A-purified antibodies reproduced the hippocampal immunolabeling of all patients' antibodies and colocalized with them at the plasma membrane. These findings indicate that in a young woman with acute psychiatric symptoms, seizures, and central hypoventilation, a paraneoplastic immune-mediated syndrome should be considered. Recognition of this disorder is important because despite the severity of the symptoms, patients usually recover. The location and function of the isolated antigen suggest that the disorder is directly mediated by antibodies.

Paraneoplastic limbic encephalitis in a teenage girl with an immature ovarian teratoma

Paraneoplastic limbic encephalitis (PLE) is an unusual disorder that is characterized by the association of clinical limbic system abnormalities with neoplasia, usually malignancy. It has rarely been reported in children and then manifests during the teenage years. Diagnosis is often delayed, especially when the tumor has not been recognized. In adults, the diagnosis can be revealed by the presence of antineuronal antibodies. We describe an unusual case of behavioral disturbance leading rapidly to coma in a 14-year-old girl with CSF pleocytosis who was found 10 weeks later to have an immature ovarian teratoma. Although her symptoms eventually improved slightly after tumor excision, she died while in rehabilitation. PLE is an important diagnosis to consider in the teenage girl with symptoms of a progressive limbic disorder and CSF pleocytosis, and whose brain MR imaging demonstrates no abnormality or mild T2-weighted temporal lobe signal abnormality. When this constellation of findings presents in a teenage girl, the possibility of an underlying ovarian teratoma should be considered.

Paraneoplastic Limbic Encephalitis: Ovarian Cancer Presenting as an Amnesic Syndrome

BACKGROUND

Paraneoplastic limbic encephalitis (PLE) is a rare neurologic manifestation of malignancy. Paraneoplastic limbic encephalitis typically presents with short-term memory loss, seizures, or other limbic system abnormalities. The majority of PLE cases are associated with lung and testicular cancer.

CASE

We present the first case of PLE attributable to an epithelial ovarian cancer. The 58-year-old woman presented with rapidly progressing short-term memory loss and amnesia. The diagnosis of ovarian cancer was suspected on the basis of computed tomography scan findings. The patient showed dramatic clinical improvement within 2 weeks of debulking surgery and after the initiation of plasmapheresis and chemotherapy.

CONCLUSION

Paraneoplastic limbic encephalitis is a rare complication of ovarian tumors that is potentially reversible with prompt surgical management of the primary tumor, plasmapheresis, and chemotherapy.

Bilateral horizontal gaze palsy in presumed paraneoplastic brainstem encephalitis associated with a benign ovarian teratoma

A 28-year-old woman with a previous history of recurrent benign ovarian teratoma developed a bilateral horizontal gaze palsy, a right facial paresis, and bilateral trigeminal hypesthesia. Magnetic resonance imaging disclosed high signal in the rostral pons. Results of all other laboratory studies, including those for antineuronal antibodies (anti-Hu, anti-Yo, anti-Ri, anti-Tr, anti-Ma1, anti-Ma2, and anti-CV2/CRMP5), were negative. Pelvic ultrasound revealed a residual mass in the left ovary, which was confirmed as teratoma on surgical pathological examination. Complete neurologic recovery occurred within two weeks of surgical removal of the teratoma and treatment with intravenous corticosteroids and immunoglobulin. This case demonstrates that a search for an occult neoplasm is extremely important in the diagnosis of presumed paraneoplastic encephalitis even if antineuronal antibodies are not found.