Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS): contemporary advances and current controversies.

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is an inflammatory syndrome with characteristic clinical, radiological, and pathological features, and can be effectively treated with corticosteroid-based immunotherapies. The exact pathogenesis of CLIPPERS remains unclear, and specific diagnostic biomarkers are not available. According to the 2017 diagnostic criteria, probable CLIPPERS should be considered in middle-aged patients with subacute onset of pontocerebellar symptoms and typical punctuate and curvilinear gadolinium enhancement lesions ("salt-and-pepper" appearance) located in the hindbrain (especially pons) on magnetic resonance imaging. In addition, CLIPPERS-mimics, such as central nervous system (CNS) lymphoma, and several antibody-associated autoimmune CNS diseases (e.g., myelin oligodendrocyte glycoprotein antibody-associated disease, autoimmune glial fibrillary acidic protein astrocytopathy, and anti-N-methyl-D-aspartate receptor encephalitis), should be extensively excluded. The prerequisite for definite CLIPPERS is the perivascular T-cell-predominant inflammatory infiltration observed on pathological analysis. A biopsy is strongly suggested when clinical/radiological red flags are present. Most patients with CLIPPERS respond well to corticosteroids and have a good prognosis. Long-term low-dose corticosteroid maintenance therapy or corticosteroids coupled with immunosuppressants are recommended to prevent the recurrence of the syndrome. The potential progression of CLIPPERS to lymphoma has been suggested in some cases; therefore, at least 2-year clinical and radiological follow-up is essential. Here, we critically review the recent developments and provided an update on the clinical characteristics, diagnostic criteria, differential diagnoses, and therapeutic management of CLIPPERS. We also discuss the current controversies in this context that can be resolved in future research studies.

Keyhole Retrosigmoid Craniotomy for Lateral Pontine Cavernous Malformation.

With improvements in anesthesia, monitoring, and peroperative care, the surgical removal of intrinsic brainstem pathology has become a possibility.1 Although surgical removal of deep-seated lesions continues to have significant morbidity, at least temporarily, associated with it, removal of exophytic lesions can be accomplished with little disability for the patient. The key to a good outcome, when removing cerebral cavernous malformation, is preservation of adjacent neurovascular bundles, use of sharp dissection over blunt pulling, judicious use of cautery in and around the brainstem, and preservation of the developmental venous anomaly, when present. The authors present a case of a lateral pontine cerebral cavernous malformation that was exophytic at the lateral and peritrigeminal safe entry zones.2 Neuromonitoring was used an adjunct to ensure safety of the procedure. The lesion is accessed using a keyhole retrosigmoid craniotomy (Video 1). We do not routinely use lumbar drains for these procedures as careful arachnoid dissection can result in adequate cerebrospinal fluid release. The window of access to this area is between CN 5 and the CN 7/8 complex. The arachnoid over the nerves is preserved, but the layer between the nerves is exposed to gain access to the lateral pons. The lesion is sharply dissected from the lateral pons, taking care to save the developmental venous anomaly, from which this lesion arises.

Clinical outcomes of stereotactic biopsy on children with pontine diffuse midline glioma.

INTRODUCTION: Diffuse midline glioma (DMG) of the pons occurs in pediatric patients and carries a dismal prognosis. Biopsy is not necessary for diagnosis but provides information, particularly H3K27M status, with prognostic implications. Additionally, biopsy information may open therapeutic options such as clinical trials that require mutation status. Therefore, we sought to assess the safety of surgical biopsy in DMG patients as well as its potential impact on clinical course. METHODS: Retrospective analysis of patients who were radiographically and clinically diagnosed with pontine DMG in the last 5 years was performed. We assessed demographic, clinical, radiographic, surgical, and follow-up data. RESULTS: 25 patients were included; 18 (72%) underwent biopsy while 7 (28%) declined. 12 biopsies (67%) were performed with robotic arm and 5 (27%) with frameless stereotaxy. Three biopsied patients (17%) experienced new post-operative neurologic deficits (1 facial palsy, 1 VI nerve palsy and 1 ataxia) that all resolved at 2-week follow-up. All biopsies yielded diagnostic tissue. Fourteen patients (78%) had H3K27M mutation. Median OS for H3K27M patients was 10 months compared to 11 months in the wild-type patients (p = 0.30, log-rank test). Median OS for patients enrolled in clinical trials was 12 months compared to 8 months for non-trial patients (p = 0.076). CONCLUSION: In our series, stereotactic pontine DMG biopsies did not carry any permanent deficit or complication and yielded diagnostic tissue in all patients. Similar post-operative course was observed in both robot-assisted and frameless stereotactic approaches. There was no significant difference in survival based on mutation status or clinical trial enrollment.

Recurrent haemorrhagic pontine cavernoma resection via a retrosigmoid microsurgical approach.

BACKGROUND: Brainstem cavernomas occasionally require surgical treatment. Appropriate patient selection and thorough understanding of the anatomy and technical nuances involved in microsurgical resection is a pre-requisite in undertaking these challenging cases. CASE DESCRIPTION: We present a video case of a patient with a recurrent haemorrhagic pontine cavernoma. A step-by-step commentary of surgical footage is provided along with clinical, anatomical and technical learning points pertinent to the safe surgical management of these lesions.

Long-standing myoclonic hand tremor as an isolated symptom of hypertrophic olivary degeneration.

Hypertrophic olivary degeneration (HOD) is a rare condition caused by lesions of the dentato-rubro-olivary pathway, usually bilateral. We presented a case of a 64-year old male with HOD caused by a unilateral, posterior pontine cavernoma. The patient has not developed the typical palate myoclonus until recently. Isolated hand myoclonus with coexisting asterixis was present for years. This case shows unique HOD symptomatology and emphasizes the important role of MRI in the differential diagnosis of monomelic myoclonus.

Fifty years of DIPG: looking at the future with hope.

Diffuse intrinsic pontine glioma (DIPG) is a primary brainstem tumor of childhood that carries a dismal prognosis, with median survival of less than 1 year. Because of the brain stem location and pattern of growth within the pons, Dr. Harvey Cushing, the father of modern neurosurgery, urged surgical abandonment. Such a dismal prognosis remained unchanged for decades, coupled with a lack of understanding of tumor biology and an unchanging therapeutic panorama. Beyond palliative external beam radiation therapy, no therapeutic approach has been widely accepted. In the last one to two decades, however, increased tissue availability, an improving understanding of biology, genetics, and epigenetics have led to the development of novel therapeutic targets. In parallel with this biological revolution, new methods intended to enhance drug delivery into the brain stem are contributing to a surge of exciting experimental therapeutic strategies.

Deceptive Appearances - Spastic Paretic Hemifacial Contractures in Cases of Seventh Nerve Involvement 'Inside' and 'Outside' the Brainstem.

Spastic paretic hemifacial contracture (SPHC) is a rare clinical phenomenon characterized by facial weakness and simultaneous well-sustained contraction of the unilateral half of the face, mimicking a paresis of the normal contralateral side on casual inspection. We present three cases with such phenomenon and have postulated the underlying mechanisms. One patient had intrinsic brainstem glioma, and the others were operated for extra-axial lesions compressing the pons. The former presented with SPHC, whereas the latter two gradually developed this phenomenon following postoperative facial paresis. This condition is possibly due to denervation hyper-excitability of the facial supranuclear pathway or an aberrant regeneration secondary to nerve injury leading to functional facial-nerve nuclear reorganization. SPHC occurrence is not limited to intra-axial lesions but can also be seen after partial injury to the facial nerve beyond its exit from the brainstem.

DIPG-like MYB-altered diffuse astrocytoma with durable response to intensive chemotherapy.

Pontine gliomas represent difficult to treat entity due to the location and heterogeneous biology varying from indolent low-grade gliomas to aggressive diffuse intrinsic pontine glioma (DIPG). Making the correct tumor diagnosis in the pontine location is thus critical. Here, we report a case study of a 14-month-old patient initially diagnosed as histone H3 wild-type DIPG. Due to the low age of the patient, the MRI appearance of DIPG, and anaplastic astrocytoma histology, intensive chemotherapy based on the HIT-SKK protocol with vinblastine maintenance chemotherapy was administered. Rapid clinical improvement and radiological regression of the tumor were observed with nearly complete remission with durable effect and excellent clinical condition more than 6.5 years after diagnosis. Based on this unexpected therapeutic outcome, genome-wide DNA methylation array was employed and the sample was classified into the methylation class "Low-grade glioma, MYB(L1) altered." Additionally, RT-PCR revealed the presence of MYB::QKI fusion. Taken together, the histopathological classification, molecular-genetic and epigenetic features, clinical behavior, and pontine location have led us to reclassify the tumor as a pontine MYB-altered glioma. Our case demonstrates that more intensive chemotherapy can achieve long-term clinical effect in the treatment of MYB-altered pontine gliomas compared to previously used LGG-based regimens or radiotherapy. It also emphasizes the importance of a biopsy and a thorough molecular investigation of pontine lesions.

[Reversible central pontine myelinolysis without hyponatremia in a child with acute lymphoblastic leukemia: a case report]. / Myélinolyse centropontine réversible sans hyponatrémie chez un enfant atteint de leucémie aigüe lymphoblastique: à propos d'un cas.

Central pontine myelinolysis is a demyelinating disorder mainly affecting the central pons. In some cases, it is associated with extrapontine myelinolysis. It is usually caused by rapid correction of hyponatremia and osmotic shock. We here report the case of a 3.5-year-old girl diagnosed with acute lymphoblastic leukemia admitted to our Oncology Unit with neutropenic fever and diarrhea. Laboratory tests showed mild neutropenia, normochromic normocytic anemia. Electrolyte tests were normal without hyponatremia. She received antibiotic therapy with Metronidazole. Five days later, she developed flaccid quadriparesis with mutism. Computerized tomography (CT) scan was normal, cerebrospinal fluid (CSF) examination was normal (there was no evidence of leukemic cells) and ophthalmological examination did not show any abnormalities. Brain MRI found hyperintense signal in the pons. The child improved without specific treatment, and clinical and complete neurological recovery was noted. This case highlights that myelinolysis can occur under some circumstances not related with hyponatremia such as malignancy, chemotherapy.

Fetal Pontine Tegmental Cap Dysplasia- A Case Report.

Pontine tegmental cap dysplasia (PTCD) is a very rare hindbrain malformation recently described and the affected children show a bad prognosis. We present this case to increase the awareness of this rare condition and to highlight the importance of early prenatal diagnosis. A 25 years old female with 22 weeks gestation was referred after sonography for fetal magnetic resonance imaging (MRI) in the evaluation of cerebellar hypoplasia. Prenatal MRI confirmed cerebellar hypoplasia. Follow up postnatal MRI showed flattening of the ventral pons, beak-like tissue in the posterosuperior pons suggesting the diagnosis of PTCD. In retrospect the fetal MR images revealed features consistent with PTCD. To the best of our knowledge, this is the fifth prenatal case and with the earliest gestational age of 22 weeks.

Clinical characteristics, management, and outcomes of CLIPPERS: A comprehensive systematic review of 140 patients from 100 studies.

INTRODUCTION: Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a rare inflammatory disorder of the central nervous system, characterized by symptoms referable to the brainstem and cerebellum such as, diplopia, gait ataxia and cerebellar dysarthria. The features and outcomes of CLIPPERS remains uncertain. we conducted this comprehensive systematic review to summarize all the existing studies that described CLIPPERS in the literature and to provide a quantitative assessment on the clinical characteristics, management, and outcomes of this rare syndrome. METHODS: A comprehensive search of PubMed and Web of Science databases was conducted from inception until January 15, 2022, was conducted. We only included the cases that clearly reported probable or definite diagnosis of CLIPPERS based on Taieb et al.'s criteria. The quality of the included studies was assessed using the JBI Critical Appraisal Tool. Descriptive statistics were performed to analyze the studies. Data were expressed as mean and standard deviation (SD) for continuous variables and proportions for categorical variables. RESULTS: We identified 100 case reports and series including a total of 140 patients with CLIPPERS (mean age: 46±18 years and males were 60%). The average follow-up duration was 32.27±57.8 months. Ataxia was the most common presenting symptom. Sixteen percent of the cases were associated with malignancy, mostly hematologic malignancies. The overall relapse rate was 59.2%, and the duration of steroid therapy was considerably shorter in the relapsed cases than in the non-relapsed (mean 6.19±7.9 vs. 10.14±12.1 days, respectively, P = 0.04). The overall mortality rate was 10%, but mortality in patients with malignancy was 30% and it was 12% in patients with relapses. In the case of steroid dosing (less than 20 mg/d versus greater than 20 mg/d) there was no significant modification in the risk of relapse. CONCLUSION: CLIPPERS is a rare clinical syndrome that affects mainly middle-aged males. Diagnosis of CLIPPERS is often challenging, and delays in diagnosis and treatment can lead to unfavorable outcomes. Therefore, neurologists should maintain a high index of suspicion for CLIPPERS in any patient presenting with symptoms and signs referrable to the brainstem. These patients should be screened for associated malignancies, especially hematological malignancies. The cases associated with malignancy tend to have worse outcomes. The relapse rate is relatively high. The relapse rate may be associated with worse mortality. Based on our findings, we recommend that CLIPPERS be treated with high-dose steroid therapy for at least ten days during the acute phase with a very slow taper. Prospective studies with a larger sample size are needed to validate our findings and guide the clinical care of these patients.

Disseminated diffuse midline glioma associated with poorly differentiated orbital lesion and metastases in an 8-year-old girl: case report and literature review.

BACKGROUND: Disseminated diffuse midline glioma (DMG) is a devastating diagnosis. Molecular subtyping has increased our understanding of this tumor. CASE: Here, we report the case of an 8-year-old girl who presented with symptoms of brainstem dysfunction and was found to have disseminated DMG with lesions in the pons, thalamus and bilateral temporal lobes. Molecular subtyping of the temporal lobe tumor tissue was consistent with H3 K27me3 loss and EZHIP overexpression, falling under the newly designated "H3 K27-altered" AQ5WHO subtype of DMG. Pathology from biopsy of the orbital lesion showed poorly differentiated rhabdoid-like disseminated tumor cells. The patient went on to develop lesions in the peritoneum, infratemporal fossa, and along the lumbosacral nerve roots. CONCLUSION: This unique case illustrates the aggressive behavior of H3 K27-altered tumors and their potential to metastasize.

Space occupying lesion presenting as Millard-Gubler syndrome.

Millard-Gubler syndrome (MGS) is a ventral pontine syndrome due to an ipsilateral involvement of abducens and facial nerve with a contralateral hemiparesis or hemiplegia. Although classically described as a vascular brainstem syndrome, various other aetiologies such as infection or demyelination may lead to MGS. In this case, a young female presented with MGS, which was attributed to a strategically located infective granuloma of the brainstem. In countries, where tuberculosis is still considered an endemic, central nervous system involvement due to tuberculosis may have protean manifestations.

Leptomeningeal and subependymal seeding of diffuse intrinsic pontine glioma: a case report.

DIPG (diffuse intrinsic pontine glioma) is a deadly cancerous tumor of the brainstem that spreads across the pons. The tumor's infiltrative nature, as well as the tumor's critical pathway and nuclei compression, contributes to the tumor's extremely poor prognosis and limited existing therapeutic options. A previous study revealed that in 40 patients with brainstem glioma, 13 (33%) patients had leptomeningeal spreading. In this paper, we reported a 7-year-old female patient who presented with a history of decreased consciousness and weakness of the right limb. Her magnetic resonance imaging (MRI) revealed a pontine mass. She was given 35 fractions of 54 Gy whole-brain radiotherapy. The post-radiotherapy MRI evaluation showed multiple nodules in periventricular region, and was suggestive of leptomeningeal and subependymal seeding of the pontine glioma in the lateral ventricles. This case report elucidated the leptomeningeal seeding in a pediatric patient with diffuse intrinsic pontine glioma.

Thirteen-and-a-half Syndrome Secondary to the Brainstem Cavernoma.

Background: "Thirteen-and-a-half" is a newly described clinical syndrome characterized by the combination of the one-and-a-half syndrome with fifth and seventh cranial nerve nuclei involvement (11/2 + 5 + 7 = 131/2). To the authors' knowledge, this is the first report of the thirteen-and-a-half syndrome secondary to pontine cavernoma and, overall, only the second reported case of this syndrome in the literature till date. Case Report: A 20-year-old man presented with the clinical features suggestive of the thirteen-and-a-half syndrome, explained radiologically by pontine cavernoma. We operated him using a suboccipital transvermian approach and he is doing well at 2.5 years follow-up. Interestingly, his one-and-a-half syndrome has partially improved to left horizontal gaze palsy. Conclusion: The clinical appreciation of the thirteen-and-a-half syndrome precisely localizes the lesion to ipsilateral dorsal pontine tegmentum. Neurosurgeons must be aware of the newly described "one-and-a-half- plus" syndromes as they help in a better understanding of pathoanatomy caused by different disease processes in the brainstem.

Neurogenic bladder as a lurking complication in Moebius syndrome.

Moebius syndrome (MBS) is a congenital disorder characterized by facial and abducens palsy, sometimes accompanied with other cranial nerve palsies and comorbid conditions. Anatomical anomalies of the brainstem are assumed to be major etiologies of MBS. Its phenotypic presentation can be variable. We report a female patient with MBS who presented with neurogenic bladder (NB). She was born via normal vaginal delivery. At birth, she showed bilateral abducens palsy and right facial palsy. We diagnosed MBS by cranial computed tomography scan and magnetic resonance imaging. She had recurrent urinary tract infection. Hydronephrosis was noted on ultrasonography and bilateral vesicoureteral reflux (grade 5) on voiding cystourethrography. Urodynamic investigation showed detrusor overactivity and detrusor-sphincter dyssynergia, which follow the pattern of NB resulting from infrapontine-suprasacral lesions. Patients with MBS have lower brainstem dysfunction, and accordingly we should be aware of NB.

Motor Organization in Schizencephaly: Outcomes of Transcranial Magnetic Stimulation and Diffusion Tensor Imaging of Motor Tract Projections Correlate with the Different Domains of Hand Function.

OBJECTIVE: Schizencephaly is a rare congenital malformation that causes motor impairment. To determine the treatment strategy, each domain of the motor functions should be appropriately evaluated. We correlated a color map of diffusion tensor imaging (DTI) and transcranial magnetic stimulation (TMS) with the hand function test (HFT) to identify the type of hand function that each test (DTI and TMS) reflects. Further, we attempted to demonstrate the motor neuron organization in schizencephaly. METHOD: This retrospective study was conducted on 12 patients with schizencephaly. TMS was conducted in the first dorsal interosseous (FDI), biceps (BB), and deltoid muscles of the upper extremity, and contralateral MEP (cMEP) and ipsilateral MEP (iMEP) were recorded. The HFT included the grip strength, box and block (B&B), and 9-hole peg test. The schizencephalic cleft was confirmed using magnetic resonance imaging, and the corticospinal tract (CST) was identified using the color map of DTI. The symmetry indices for the peduncle and CST at pons level were calculated as the ratios of the cross-sectional area of the less-affected side and that of the more-affected side. RESULT: In the more-affected hemisphere TMS, no iMEP was obtained. In the less-affected hemisphere TMS, the iMEP response was detected in 9 patients and cMEP in all patients, which was similar to the pattern observed in unilateral lesion. Paretic hand grip strength was strongly correlated with the presence of iMEP (p = 0.044). The symmetry index of the color map of DTI was significantly correlated with the B&B (p = 0.008, R 2 = 0.416), whereas the symmetry index of the peduncle was not correlated with all HFTs. CONCLUSION: In patients with schizencephaly, the iMEP response rate is correlated with the hand function related to strength, while the symmetricity of the CST by the color map of DTI is correlated with the hand function associated with dexterity. Additionally, we suggest the possible motor organization pattern of schizencephaly following interhemispheric competition.

Parotid carcinoma following chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids: a case report.

BACKGROUND: Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is an inflammatory disorder with unclear causes. Paraneoplastic etiology may be a cause. We report a case of CLIPPERS with parotid carcinoma. CASE PRESENTATION: A 54-year-old man with a history of lymphoma was hospitalized with a pontocerebellar syndrome. Brain MRI revealed that the pons and cerebellum were "peppered" with punctate and curvilinear enhancement lesions that supported the diagnosis of CLIPPERS. The relapse of lymphoma was excluded by a further cerebellum biopsy revealing predominantly CD3+ T cells in white matter. The patient was relieved after pulse therapy with intravenous methylprednisolone and a large dose of corticosteroids, but he complained of a worsening gait problem when corticosteroids were tapered to a lower dose. Although the clinical symptoms gradually improved again by increasing the dosage of corticosteroids with Azathioprine, the patient still had a slight unsteady gait during follow-up. At the 7-month follow-up, a parotid mass was detected by MRI and was verified as carcinoma by biopsy. After resection of parotid carcinoma, the residual symptoms and previous MRI lesions disappeared, and no relapse occurred. CONCLUSIONS: CLIPPERS may not be a distinct nosologic entity but an overlapping diagnosis with other diseases. Some cases of CLIPPERS might be a subtype of paraneoplastic neurological syndromes (PNS) due to the similar mechanism of antibody-mediated encephalitis. Tumor screening and serum paraneoplastic autoantibody tests are recommended for patients with CLIPPERS, especially for those who relapse when corticosteroids treatment is stopped or tapered.

Chronic lymphocytic infiltration with pontine perivascular enhancement responsive to steroids (CLIPPERS) and its association with Epstein-Barr Virus (EBV)-related lymphomatoid granulomatosis: a case report.

BACKGROUND: Chronic lymphocytic infiltration with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a neuro-inflammatory syndrome first described in 2010. It has a relationship with lymphoproliferative disorders that has not been fully elucidated. This case represents an unusual progression of CLIPPERS to Epstein-Barr Virus (EBV)-related lymphomatoid granulomatosis (LYG). The exact connection between CLIPPERS and LYG remains poorly understood. CASE PRESENTATION: We present a case of a 75-year-old man who was diagnosed with CLIPPERS with initial response to immunosuppression but later progressed to EBV-related LYG. EBV polymerase chain reaction (PCR) was detected in his cerebrospinal fluid (CSF), and repeat imaging revealed findings that were uncharacteristic for CLIPPERS; thereby prompting a brain biopsy which led to a diagnosis of EBV-related LYG. This case highlights the following learning points: 1) CLIPPERS cases are often part of a spectrum of lymphomatous disease, 2) CLIPPERS can be associated with EBV-related lymphoproliferative disorders such as LYG, and 3) EBV detection in CSF should prompt earlier consideration for brain biopsy in patients. CONCLUSIONS: Our case highlights the difficulty in distinguishing CLIPPERS from other steroid-responsive conditions such as neoplastic and granulomatous diseases. Given the association of CLIPPERS with EBV-related LYG as demonstrated in this case, we recommend testing for EBV in CSF for all patients with suspected CLIPPERS. An early referral for brain biopsy and treatment with rituximab should be considered for patients with suspected CLIPPERS who test positive for EBV in their CSF.