Abstracts vi194 NEURO-ONCOLOGY • NOVEMBER 2018 ics features) and PFS, which was independent of other clinicopathologic factors in both the training (P < 0.001, multivariate Cox regression) and validation (P = 0.025, multivariate Cox regression) cohorts. Radiogenomic analysis revealed that the radiomics signature was associated with the immune response, programmed cell death, cell proliferation, and vascula- ture development. A nomogram established using the radiomics signature and clinicopathologic risk factors demonstrated high accuracy and good calibration for prediction of PFS in both the training (C-index, 0.69) and validation (C-index, 0.87) cohorts. CONCLUSIONS: PFS can be predicted non-invasively in patients with LGGs by a group of radiomics features that could refect the biological processes of these tumors. NEUROLOGICAL COMPLICATIONS OF CANCER AND CANCER THERAPY NCMP-01. COMPARISON AND QUANTITATION OF HISTOPATHOLOGY ABNORMALITIES IN SURGICALLY RESECTED CEREBRAL RADIATION NECROSIS AS COMPARED WITH RECURRENT BRAIN TUMOR FOLLOWING RADIATION Lisa Rogers 1 , Curt Tatsuoka 2 , Mitchell Machtay 3 , Chaitra Badve 3 , Pallavi Tiwari 4 , Prateek Prasanna 4 , Andrew Sloan 5 , Warren Selman 3 and Mark Cohen 3 ; 1 University Hospitals-Case Medical Center, Cleveland, OH, USA, 2 Case Western University School of Medicine, Cleveland, OH, USA, 3 University Hospitals Cleveland Medical Center, Cleveland, OH, USA, 4 Case Western Reserve University, Cleveland, OH, USA, 5 University Hospitals-Cleveland Medical Center, Cleveland, OH, USA BACKGROUND The histologic features of radiation necrosis (RTN), a dysregulated repair process following brain radiation, have not been defned and distinguished from recurrent brain tumor (RBT) following brain radi- ation therapy. The aim of this study is to compare the type and severity of histologic characteristics of tissue specimens containing predominantly or totally RTN versus predominantly or totally RBT obtained at imaging progression after brain tumor radiation. METHODS Subjects were identi- fed from brain tumor pathology reports of resected recurrent/progressing MRI enhancing lesions following brain radiation at UHCMC from 2004- -2013. RTN was defned by < 20% active tumor, the remainder radiation treatment effects. RBT was defned by >80% active tumor. (Mixed cases were excluded). H & E slides were reviewed for 30 characteristics including vascular pathologies, necrosis, tumor features, tissue reaction, infammatory infltrate, blood products, and dystrophic calcifcation. Localization in grey/ white matter and leptomeninges was noted. Each characteristic was graded in quartiles by one neuropathologist. The profle was compared with origi- nal tumor when available. RESULTS 66 patients were identifed, 40 RBT (25 glioma, 15 metastasis) and 26 RTN (14 metastasis, 12 glioma). We iden- tifed signifcant differences in frequency and severity of zonal/geographic necrosis in RTN versus RBT in glioma (p=.002) and metastasis (p=.012) and nonsignifcant difference in severity of vascular hyalinization in RTN versus glioma RBT (p=0.44). Demyelination was of borderline signifcance. Fibrinoid vascular necrosis, vessel wall thickening, and RT astrocytes were not signifcantly different in RTN versus RBT of either tumor type. In some cases, necrosis and vascular pathology were similar to pretreatment histol- ogy. CONCLUSION A multivariable assessment of histologic characteristics may assist neuropathologists in interpretation of surgically resected lesions following brain tumor radiation therapy, especially when pretreatment tumor is available for comparison. We will present imaging correlations with pathology fndings. Grant support CTSC UL1TR000439 NCMP-02. MULTIPLE SCLEROSIS OUTCOMES AFTER CANCER IMMUNOTHERAPY Catherine Garcia 1 , Val Adams 1 , Lowell Anthony 1 and John Villano 2 ; 1 University of Kentucky, Lexington, KY, USA, 2 University of Kentucky UK HealthCare, Lexington, KY, KY, USA INTRODUCTION: Multiple sclerosis as an adverse event of immune checkpoint inhibitors (ICI) is rare and the outcomes remain largely unknown with limited descriptions in the literature. METHODS: We analyzed the United States Food and Drug Administration (FDA) Adverse Event Report- ing System (FAERS) database, our institutional records, and the literature for pembrolizumab, atezolizumab, nivolumab, ipilimumab, avelumab, and durvalumab two years prior their FDA approval to December 31, 2017, for all cases of newly diagnosed or MS relapse. RESULTS: We identifed 14 cases; 11 cases from FAERS, 1 case was identifed from our institution, and 2 cases from the literature. The median age was 52.5 years, with 42.8% males and 42.8% females. Indications for ICI included melanoma (6 patients), non-small cell lung carcinoma (2 cases), pleural mesothelioma (1 case), renal cell carcinoma (1 case), colorectal cancer (1 case), and was not reported in 2 cases. Two cases were identifed from pembrolizumab use, 6 cases with nivolumab, 1 case with atezolizumab, and 5 cases after ipilimumab use. No cases were reported with the use of avelumab or durvalumab. History of multiple sclerosis was confrmed in 8 cases. Mean time to beginning of symp- toms was 29 days (3 cycles). The median time to beginning of symptoms was longer in patients receiving ipilimumab (45 days, 4 cycles). Median time for symptom resolution in all the patients was 2 months. All cases required hos- pitalization, further treatment, and close follow up. Two patients died after starting therapy. CONCLUSIONS: MS may be associated with overall state deterioration, signifcant disability, and death. The benefts of ICI should be carefully assessed prior to beginning therapy in patients with a history of MS. NCMP-03. RISK FACTORS FOR SURGICAL SITE INFECTIONS AFTER CRANIOTOMY FOR PRIMARY BRAIN TUMORS Paul Krafft 2 , Nam Tran 1 , Corin Agoris 2 , Quan Tran 2 and Solmaz Sahebjam 1 ; 1 H. Lee Mofftt Cancer Center, Tampa, FL, USA, 2 University of South Florida, Tampa, FL, USA Surgical site infection (SSI) after craniotomy for primary CNS tumors can have detrimental consequences by delaying chemoradiation treatment. The authors performed a retrospective chart review of all patients who underwent craniotomies for resection of primary brain tumors at the Mofftt Cancer Center from 2004–2014. Multivariate logistic analysis was used to identify independent risk factors. A total of 864 patients underwent craniotomies for primary brain tumors, but 65 were excluded due to insuffcient followup or incomplete records. We identifed 30 patients with SSI (3.8%). The most com- mon microorganisms isolated from SSI were methicillin resistant Staphylo- coccus aureus (40%), methicillin sensitive Staphylococcus aureus (17%), methicillin resistant Streptococcus epidermidis (7%), Pseudomonas (7%), Enterobacteriaceae (7%), and E coli (7%). During the latter part of this time period, we initiated a program of intraoperative topical vancomycin applica- tion. We observed a signifcant reduction in SSI among those receiving top- ical vancomycin compared to those without (0.8% vs 4.9%, p<0.001). The cohorts were similar in demographics and baseline comorbidities, KPS, tumor characteristics, and surgical factors. We identifed length-of-stay, previous radiation and preoperative steroid dose as independent risk factors for SSI. Thus, our study identifes potential modifable risk factors for the prevention of SSI in patient undergoing craniotomy for primary CNS tumors. NCMP-05. RITUXIMAB AS INITIAL THERAPY FOR THE REVERSAL OF MYASTHENIA GRAVIS NEUROTOXICITY CAUSED BY IPILIMUMAB/NIVOLUMAB Neha Verma 1 , Muhammed Jaffer 2 , Edwin Peguero 1 and Sepideh Mokhtari 3 ; 1 H. Lee Mofftt Cancer Center, Tampa, FL, USA, 2 University of South Florida, Tampa, FL, USA BACKGROUND: In patients with melanoma treated with immune check- point inhibitors (ICIs), neurological toxicities developed in 1% treated with Ipilimumab and 3% after Nivolumab. This rises to 14% when co-adminis- tered. Patients treated with ICIs are susceptible to Myasthenia Gravis like syndrome. There are several case reports that demonstrate the benefts of rituximab in both acetylcholine receptor (AChR) and muscle specifc kinase (MuSK) antibody-positive MG patients. This study demonstrates the beneft of Rituximab in early goal therapy. OBSERVATION: A 70 year old female with scalp dermal spindle cell melanoma participating in a clinical trial with Nivolumab versus Ipilimumab/Nivolumab presented with diplopia. She suffered from shortness of breath and intermittent bilateral eye ptosis. Her ophthalmologic symptoms started following cycle one of therapy. Her oph- thalmologist and allergist felt she had allergies. Her symptoms worsened with generalized muscle weakness and horizontal diplopia. One year later, her neurologist diagnosed her with Myasthenia Gravis. She did not receive treatment and had diffculty contacting her neurologist. She saw her pulmo- nologist for worsening dyspnea and her pulmonary function test showed a decreased negative inspiratory force (NIF) < 20 cm H2O. She declined admis- sion and was treated with Mestinon 60 mg q4hr and prednisone 90 mg. Her NIF and FVC did not improve and she was given IVIG for 5 days. Her PFTs had only slightly improved. She received 1 dose of Rituximab at 375 mg/m2 and her FVC improved to >2.5 L. She was discharged on prednisone 40 mg daily and Mestinon 60 mg TID. Three days after Rituximab she was com- pletely asymptomatic. DISCUSSION: Our case study shows a patient treated with immune checkpoint inhibitors developed Myasthenia gravis like syn- drome and was successfully treated with Rituximab. CONCLUSION: Our study shows the importance of Rituximab as initial therapy for the reversal of MG like syndrome caused by Ipilimumab/Nivolumab. NCMP-07. CLINICAL NEUROLOGICAL FEATURES AND ELECTROGRAPHIC PATTERNS OF PATIENTS WITH RELAPSED OR REFRACTORY LARGE B-CELL LYMPHOMA TREATED WITH AXICABTAGENE CILOLEUCEL AT MEMORIAL SLOAN KETTERING CANCER CENTER (MSKCC) Alexandra Sequeira, David Mao , Xi Chen, Edward Avila, Elena Mead, Craig S Sauter, Maria Lia Palomba, Parastoo B Dahi, Connie Lee Batlevi, Downloaded from https://academic.oup.com/neuro-oncology/article-abstract/20/suppl_6/vi194/5153918 by guest on 05 June 2020