ObjectiveTo record the MR imaging features of primary central nervous system lymphoma (PCNSL) and compare these features in monofocal and multifocal disease.Materials and MethodsTwenty-one cases of monofocal disease were compared to five cases of multifocal disease. All patients were examined by non-enhanced and contrast-enhanced MRI. Tumor location, tumor size, signal intensity, enhancement characteristics, age distribution, peritumoral edema, cystic changes, and the presence of calcifications were assessed. The MRI features were compared between the monofocal and multifocal disease cases.ResultsThe 26 cases, including both the monofocal and multifocal cases, exhibited 37 lesions. Contrast-enhanced images showed variable enhancement patterns: homogeneous enhancement (33 lesions), ring-like enhancement (2), and 'open-ring-like' enhancement (2). The 'notch sign' was noted in four of 33 homogeneously enhancing lesions. One case of hemorrhage and three cases of cystic formation were observed. Intra-tumoral calcification was not found. The frontal lobe, the corpus callosum and the basal ganglia were commonly affected in both the monofocal and multifocal groups. Tumor size differed significantly between the two groups (t = 3.129, p < 0.01) and mildly or moderately enhanced lesions were more frequently found in the monofocal group (p < 0.05). There was no statistical difference between perifocal edema (p > 0.05) and the signal characteristics (p > 0.05) between the two groups.ConclusionOur data show that PCNSL has a variable enhancement pattern on MR images. We first reported two lesions with an 'open-ring' enhancement as well as four cases with a 'notch sign'. Monofocal PCNSL cases typically have larger sized tumors with mild or moderate enhancement.

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e13002 Background: ERBB2 mutation has been found to be an oncogenic driver gene in non-small cell lung cancers (NSCLC) and ERBB2-directed therapies have shown promising results in this unique population, while little is known about ERBB2 fusion association with outcomes of afatinib. The aim of this study was to investigate the efficacy of afatinib in patients with advanced ERBB2 fusion NSCLC. Methods: A multicenter study in China was initiated from February 2014, and NSCLC patients have been enrolled as of December 2018. To determine the frequency of the ERBB2 fusions in NSCLC and other tumors, we analyzed data from 2743 clinical NSCLC cases, each of which had results from next-generation sequencing (NGS)-based 381 genes panel assay, analogous to the index patient. Results: Of this entire cohort, eight (0.29%) patients were identified with an ERBB2 fusion, including TNS4-ERBB2 (1), ERBB2-CD79B (1), IGFBP4-ERBB2 (1), ERBB2-PSMD3 (1), SEZ6-ERBB2 (1), ERBB2-PGAP3 (1), ARL5C-ERBB2 (1) and B3GNTL1-ERBB2 (1). The genes most frequently co-altered in patients with ERBB2 fusions were TP53 (37.50%), CDKN2A (25.00%), RB1 (25.00%) and RBM10 (25.00%). Overall TMB in the ERBB2 fusions was low (median 2.97 mut/Mb). For treatments, 25.00% patients chose afatinib, another patients chose chemotherapy or chemoradiotherapy, and case examples of advanced ERBB2 fusion driven NSCLC patients responding to afatinib were actively being sought thru our database. Conclusions: Patients with advanced ERBB2 fusion NSCLC showed a good outcome of afatinib compared to those with ALK/ ROS1 fusion which response to crizotinib, which strengthen the need for effective ERBB2-targeted drugs in clinical practice.

e13001 Background: Fibroblast growth factor receptors (FGFR) are transmembrane kinase proteins with growing importance in non-small cell lung cancer (NSCLC) biology given the frequency of molecular alterations and vast interface with multiple other signaling pathways. Furthermore, numerous FGFR inhibitors in clinical development demonstrate the expanding therapeutic relevance of this pathway. The aim of this study was to evaluate the prevalence of FGFR-TACC fusions in Chinese NSCLC populations, which had not been reported earlier, and to describe targeting potential in Chinese NSCLC populations. Methods: A multicenter study in China was initiated from February 2014, and NSCLC patients have been enrolled as of December 2018. Capture-based comprehensive genomic profiling was performed on 2743 NSCLC FFPE samples sequenced to a mean coverage depth of > 650X for up to 381 cancer-related genes. Genomic alterations (GA) included short variant (SV) base subs and insertions/deletions, copy number alterations, and rearrangements/fusions. Tumor mutational burden (TMB; mut/Mb) was calculated on up to 1.2 Mb of sequenced DNA. Results: Of this entire cohort, just 16 (0.58%) patients were identified with FGFR-TACC fusions, including FGFR1-TACC 1 fusion (1), FGFR2-TACC2 fusion (3) and FGFR3-TACC3 fusion (12). Median patient age was 57 (range 36-84 years). Of the FGFR-TACC fusion NSCLC patients, 56.25% were detected in female patients. Biopsies were obtained from primary lung tumor (31.25%) and metastatic sites (68.75%). Overall TMB in the FGFR-TACC fusion was low (median 3.6 mut/Mb), although two cases (12.50%) had > 20 mut/Mb. Of the FGFR-TACC fusion NSCLC patients, two cases (12.50%) featured EGFR SV alterations. Conclusions: FGFR-TACC fusions occur in a subset of patients with NSCLC. Such patients should be considered for clinical trials featuring FGFR inhibitors (AZD4547). Moreover, NGS can provide information for targeted therapy. For NSCLC patients to benefit from more personalized cancer treatment, clinical therapy should improve with clinical diagnostics through multi-gene assays to determine the actual clinical benefits.