Autopsy case of the cerebellar form of progressive multifocal leukoencephalopathy without immunodeficiency

MRI Shrimp Sign in Cerebellar Progressive Multifocal Leukoencephalopathy: Description and Validation of a Novel Observation

BACKGROUND AND PURPOSE

There are no validated imaging criteria for the diagnosis of progressive multifocal leukoencephalopathy in the cerebellum. Here we introduce the MR imaging shrimp sign, a cerebellar white matter lesion identifiable in patients with cerebellar progressive multifocal leukoencephalopathy, and we evaluate its sensitivity and specificity.

MATERIALS AND METHODS

We first identified patients with progressive multifocal leukoencephalopathy seen at Massachusetts General Hospital between 1998 and 2019 whose radiology reports included the term "cerebellum." Drawing on a priori knowledge, 2 investigators developed preliminary diagnostic criteria for the shrimp sign. These criteria were revised and validated in 2 successive stages by 4 additional blinded investigators. After defining the MR imaging shrimp sign, we assessed its sensitivity, specificity, positive predictive value, and negative predictive value.

RESULTS

We identified 20 patients with cerebellar progressive multifocal leukoencephalopathy: 16 with definite progressive multifocal leukoencephalopathy (mean, 46.4 [SD, 9.2] years of age; 5 women), and 4 with possible progressive multifocal leukoencephalopathy (mean, 45.8 [SD, 8.5] years of age; 1 woman). We studied 40 disease controls (mean, 43.6 [SD, 21.0] years of age; 16 women) with conditions known to affect the cerebellar white matter. We defined the MR imaging shrimp sign as a T2- and FLAIR-hyperintense, T1-hypointense, discrete cerebellar white matter lesion abutting-but-sparing the dentate nucleus. MR imaging shrimp sign sensitivity was 0.85; specificity, 1; positive predictive value, 1; and negative predictive value, 0.93. The shrimp sign was also seen in fragile X-associated tremor ataxia syndrome, but radiographic and clinical features distinguished it from progressive multifocal leukoencephalopathy.

CONCLUSIONS

In the right clinical context, the MR imaging shrimp sign has excellent sensitivity and specificity for cerebellar progressive multifocal leukoencephalopathy, providing a new radiologic marker of the disease.

Successful treatment of non-HIV progressive multifocal leukoencephalopathy: case report and literature review

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) is a subacute onset demyelinating disease caused by JC virus and characterized by multifocal involvement of the subcortical white matter and cerebellar hemispheres or peduncles on magnetic resonance imaging (MRI). However, non-HIV PML patients with brain lesions limited to the cerebellum and brainstem have not been well characterized.

METHODS

We report a 68-year-old man with systemic lupus erythematosus under treatment with immunosuppressants who developed non-HIV PML with brain lesions limited to the cerebellum and brainstem and successfully treated with a combination of mefloquine and mirtazapine. We performed a literature review to characterize patients with non-HIV PML with brain lesions limited to the cerebellum and brainstem.

RESULTS

Eight cases with non-HIV brainstem/cerebellar form PML were identified including our case. All cases had compromised status related underlying diseases. Four (50%) had a good prognosis. Five cases were treated, including 3 with favourable outcomes. Between the good prognosis group (n = 4) and the poor prognosis group (n = 4), treatment status for PML and the interval between the initial manifestation and diagnosis did not differ. Among those who performed contrast-enhanced brain imaging, lesion enhancement was related to good prognosis (good prognosis group vs. poor prognosis group; 100% vs. 0%).

CONCLUSION

PML should be considered in the differential diagnosis of brain lesions limited to the cerebellum and brainstem in immunocompromised patients. The presence of immune response against JC virus and inflammatory reactions may indicate good prognosis in non-HIV brainstem/cerebellar form PML.

An autopsy case of progressive multifocal leukoencephalopathy after rituximab therapy for malignant lymphoma

Progressive multifocal leukoencephalopathy (PML) is a rare fatal demyelinating disease of the central nervous system caused by reactivation of the JC virus (JCV), which is named after the initials of the patient from whom the virus was first isolated. JCV is highly prevalent worldwide, infects humans in early childhood, and the infection persists throughout the course of life in latent form. The present paper deals with the second autopsy case report of rituximab-associated PML in Japan. A 63-year-old woman who had undergone chemotherapy for non-Hodgkin lymphoma developed progressive dysarthria and cerebellar ataxia. Head magnetic resonance imaging (MRI) revealed small, scattered, hyperintense areas in the midbrain, pons and thalamus, and the patient was first diagnosed as having cerebral infarction. Follow-up MRI showed tendency toward cerebellar atrophy and multiple system atrophy cerebellar type was suggested, which we concluded must have coincidentally occurred. It was challenging to perform biopsy due to the location of the foci and the patient's condition. Twelve months later she died of aspiration pneumonia caused by the bulbar lesion. At autopsy, the histological examination suggested the presence of demyelinating foci with numerous foamy macrophages. In the foci, oligodendrocytes with enlarged ground-glass like nuclei were found in a scattered manner and astrocytes with bizarre nuclei were also detected. These findings verified the case as PML. The first diagnosis of cerebral infarction was later withdrawn, although appropriate disorders were not recalled even after testing with various antibodies. The rate of PML development tends to increase after treatment with molecular-targeted therapies, which directly or indirectly attenuate the cellular-mediated immune system. Various novel molecular-targeted and immunosuppressive drugs have been released on the market; the cases of PML have consequently increased. Accordingly, pathologists should keep this disease in mind in the differential diagnosis when neural symptoms newly emerge in patients who are treated with these drugs.

An unusual cause of fatal rapid-onset ataxia plus syndrome

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disorder of the central nervous system caused by reactivation of the JC-virus and is in most cases associated with underlying immunosuppression. Acquired immune deficiency syndrome (AIDS) and hematological malignancies are well-known predisposing factors for PML. However, in the past ten years, various pharmacological agents have been associated with increased risk of PML. Based on the phenomenology PML can be divided into the cerebral form and the rare cerebellar form.

CASE PRESENTATION

Here we describe a man affected by polycythemia vera (PCV) that was treated with hydroxyurea (HU) and developed PML. The initially PML presentation included ataxia as one of the main features. Brain MRI displayed widespread supratentorial and infratentorial lesions. Immunological analysis revealed absence of reactivity to a wide range of antigens. The course of disease was rapidly progressive with fatal outcome - autopsy ruled out leukemic transformation.

CONCLUSION

The occurrence of PML in PCV patients is very rare and has been reported only once. Movement disorders, such as ataxia, are also less frequent. In the present case the PML was likely multifactorial.

A case of progressive multifocal leukoencephalopathy with chronic renal failure, whose JC virus in cerebrospinal fluid disappeared after mefloquine-mirtazapine dual therapy

An 83-year-old man with chronic renal failure was referred to our hospital because of subacute progressive right hemiparesis. A brain MRI showed high-intensity lesions in bilateral middle cerebellar peduncles and white matter of the left frontal lobe on T₂-weighted images. The lesions increased gradually, so we suspected a brain tumor because ¹H-MRS images showed elevated Cho and decreased NAA, and also pathologic findings of the brain biopsy suggested glioblastoma. However, JC virus (JCV) in cerebrospinal fluid was revealed highly positive by PCR. So we reconsidered pathologically and finally found bizarre astrocytes which were infected with JCV in immunohistochemical studies and we diagnosed progressive multifocal leukoencephalopathy at last. Then we medicated with mefloquine and mirtazapine, and the JCV in cerebrospinal fluid disappeared, without new MRI lesions. This is a rare case in respect of the background of the patient and the clinical course.

High expression of MeCP2 in JC virus-infected cells of progressive multifocal leukoencephalopathy brains

Mutations of the methyl CpG binding protein 2 (MeCP2) gene are a major cause of Rett syndrome. To investigate whether the expression of this gene was related to JC virus (JCV) infection, we examined brains of four progressive multifocal leukoencephalopathy (PML) patients. JCV infection was confirmed by immunohistochemical labeling with antibodies against JCV VP1, agnoprotein and large T antigen. MeCP2 expression was examined by immunohistochemistry using a specific polyclonal antibody against MeCP2. In normal brains and uninfected cortices of PML brains, MeCP2 expression was observed in the nuclei of neurons, but not observed in glial and endothelial cell nuclei. However, in PML brains intense immunolabeling was observed in abnormally enlarged glial nuclei of JCV-infected cells. Double immunolabeling using antibodies against large T antigen (visualized as blue) and MeCP2 (visualised as red) revealed dark red JCV-infected nuclei, which confirmed that the JCV infected nuclei expressed MeCP2. We conclude that MeCP2 is highly expressed in the JCV-infected nuclei of PML brain and these results may provide a new insight into the mechanism which regulates the MeCP2 expression in glial cells by the infection of JCV.

Progressive multifocal leukoencephalopathy in individuals with minimal or occult immunosuppression

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) is a deadly demyelinating disease of the brain, caused by reactivation of the polyomavirus JC (JCV). PML has classically been described in individuals with profound cellular immunosuppression such as patients with AIDS, haematological malignancies, organ transplant recipients or those treated with immunosuppressive or immunomodulatory medications for autoimmune diseases. METHODS AND CASE REPORTS: The authors describe five HIV seronegative patients with minimal or occult immunosuppression who developed PML including two patients with alcoholic cirrhosis, one with untreated dermatomyositis and two with idiopathic CD4(+) T cell lymphocytopenia. The authors performed a review of the literature to find similar cases.

RESULTS

The authors found an additional 33 cases in the literature. Of a total of 38 cases, seven (18.4%) had hepatic cirrhosis, five (13.2%) had renal failure, including one with concomitant hepatic cirrhosis, two (5.2%) were pregnant women, two (5.2%) had concomitant dementia, one (2.6%) had dermatomyositis, and 22 (57.9%) had no specific underlying diagnosis. Among these 22, five (22.7%) had low CD4(+) T cell counts (0.080-0.294x10(9)/l) and were diagnosed as having idiopathic CD4(+) lymphocytopenia, and one had a borderline CD4(+) T cell count of 0.308x10(9)/l. The outcome was fatal in 27/38 (71.1%) cases within 1.5-120 months (median 8 months) from onset of symptoms, and 3/4 cases who harboured JCV-specific T cells in their peripheral blood had inactive disease with stable neurological deficits after 6-26 months of follow-up.

DISCUSSION

These results indicate that PML can occur in patients with minimal or occult immunosuppression, and one can revisit the generally accepted notion that profound cellular immunosuppression is a prerequisite for the development of PML.

Cerebral white matter: neuroanatomy, clinical neurology, and neurobehavioral correlates

Lesions of the cerebral white matter (WM) result in focal neurobehavioral syndromes, neuropsychiatric phenomena, and dementia. The cerebral WM contains fiber pathways that convey axons linking cerebral cortical areas with each other and with subcortical structures, facilitating the distributed neural circuits that subserve sensorimotor function, intellect, and emotion. Recent neuroanatomical investigations reveal that these neural circuits are topographically linked by five groupings of fiber tracts emanating from every neocortical area: (1) cortico-cortical association fibers; (2) corticostriatal fibers; (3) commissural fibers; and cortico-subcortical pathways to (4) thalamus and (5) pontocerebellar system, brain stem, and/or spinal cord. Lesions of association fibers prevent communication between cortical areas engaged in different domains of behavior. Lesions of subcortical structures or projection/striatal fibers disrupt the contribution of subcortical nodes to behavior. Disconnection syndromes thus result from lesions of the cerebral cortex, subcortical structures, and WM tracts that link the nodes that make up the distributed circuits. The nature and the severity of the clinical manifestations of WM lesions are determined, in large part, by the location of the pathology: discrete neurological and neuropsychiatric symptoms result from focal WM lesions, whereas cognitive impairment across multiple domains--WM dementia--occurs in the setting of diffuse WM disease. We present a detailed review of the conditions affecting WM that produce these neurobehavioral syndromes, and consider the pathophysiology, clinical effects, and broad significance of the effects of aging and vascular compromise on cerebral WM, in an attempt to help further the understanding, diagnosis, and treatment of these disorders.

Progressive multifocal leukoencephalopathy showing extensive spinal cord involvement in a patient with lymphocytopenia

A 64-year-old Japanese man who was diagnosed as having cerebral infarcts at an early clinical stage was found to have progressive multifocal leukoencephalopathy (PML). A decrease of leukocytes and lymphocytes had been detected in the previous year. During a total clinical course of 11 months, he showed marked depletion of lymphocytes ranging from 264/microL to 459/microL. Autopsy disclosed no underlying diseases such as malignancies or tuberculosis. Extensive PML lesions were seen in the cerebral white matter. Small perivascular cuffs comprising many CD8+ T lymphocytes and a few CD4+ T cells were scattered in the PML lesions. CD20+ B cells were rarely evident. The subsets of the infiltrating lymphocytes differed from those of primary or spontaneous PML. Similar extensive PML lesions were observed not only in the cerebellum and brainstem but also in the spinal cord. All 26 segments of the spinal cord, especially the cervical, lumbar and sacral cord, showed extensive lesions involving the lateral and anterior columns. To our knowledge, only three cases of PML with such extensive spinal cord lesions have been reported previously. These three cases, and the present one, may represent a group of PML that shows extensive lesions in the spinal cord as well as the cerebrum, cerebellum and brainstem. The underlying disease in the present case was unclear. Because lymphocytopenia is not observed in primary or spontaneous PML, and the immunohistochemical findings of the infiltrating lymphocytes in the present case are different from primary or spontaneous PML, the decrease in his total blood lymphocytes may have played a significant role in his immunosuppressed condition as the underlying disease.

Congenital anaplastic astrocytoma differentiated into pilocytic astrocytoma: an autopsy case

We report an autopsy case of congenital astrocytoma and its histopathological changes during 5 years of the patient's development from birth to death. At birth, a right exophthalmic tumor was observed, and MRI revealed that the tumor occupied the right orbital space and had also affected the suprasellar diencephalic structures. The right orbital tumor, which was enucleated at 2 months of age, was a highly cellular tumor with moderate pleomorphism resembling anaplastic astrocytoma. On the other hand, at autopsy, a brain tumor was found in the right diencephalic region with features of pilocytic astrocytoma, accompanied by leptomeningeal dissemination. A biopsy specimen, which was obtained from the chiasmatic part of the tumor at 4 months of age, showed an intermediate appearance between the orbital tumor and the brain tumor obtained at autopsy. Immunohistochemical examination confirmed that all three phases of the tumors showed an astrocytic lineage, and the Ki-67 labeling index decreased rapidly after 2 months of age. We believe that this congenital anaplastic astrocytoma differentiated into a pilocytic astrocytoma during the 5 years of the patient's development. The transformation of the congenital astrocytoma from anaplastic to pilocytic forms can be attributed to the nature of the tumor, namely postmitotic neoplastic cells are characterized by their ability to undergo self-differentiation, along with the organotropism of the developing brain.

Progressive multifocal leukoencephalopathy developing in advanced pulmonal sarcoidosis

Coincidence of pulmonal sarcoidosis and progressive multifocal leukoencephalopathy (PML) rarely occurs. So far an entire course has been recorded in only very few cases. We demonstrate the case of a 49-year-old male developing an infratentorial localized PML in the setting of advanced pulmonal sarcoidosis. PML was not included in the diagnostic considerations in the first instance. Regarding the diagnosis of pulmonal sarcoidosis proved by lung biopsy, the neurological impairment was first thought to be due to a neurosarcoidosis. But magnetic resonance tomography (MRI) clearly showed a demyelination process in the cerebellum. Because of the inconsistency of the radiological findings with a neurosarcoidosis the diagnosis of an acute disseminated encephalomyelitis (ADEM) was favoured. Therefore, the patient was initially treated with corticosteroids. Because of increasing deterioration further diagnostic testings were performed. In the cerebrospinal fluid (CSF) as well as in the paraffin-embedded tissue of a stereotactical brain biopsy JCV-DNA was successfully demonstrated by PCR. Cidofovir was administered. The progression of the disease could not be influenced. The patient died 5 months after the first neurological symptoms. This report stresses the diagnostic difficulties considering patients with sarcoidosis and neurological symptoms.

Progressive Multifocal Leukoencephalopathy in an Immunocompetent Taiwanese Patient

Progressive multifocal leukoencephalopathy (PML) is a deadly demyelinating brain disease caused by JC virus (JCV). Genomic analysis of viral isolates in these cases often shows prototype-like JCV and its variants, which is a virulent strain compared to the latent archetype virions mostly found in the kidney. Here, we report a 57-year-old man who suffered from a subacute course of cognitive impairment and multiple neurologic deficits. Neuroimaging, pathology, and virology studies showed multifocal leukoencephalopathy and the presence of JCV deoxyribonucleic acid in the cerebrospinal fluid. The prototype type 1 (Mad-1) strain of JCV was identified on viral genotyping obtained from brain tissue. No immune deficits were found. He responded poorly to alpha-interferon and antiviral treatment. This case suggests that lack of immune deficiency cannot exclude the possibility of PML as a cause of subacute leukoencephalopathy. Accumulated data with respect to the disease course, pathologic feature, and viral genomic subtyping may pave the way for future treatment against this devastating disease.