literature, especially in relation to histopathological examination. Although the clinical disease course of our patient following allogeneic HSCT resembled an "MS-like" relapsing remitting encephalomyelitis, the autopsy examination did not show any evidence of active inflammation. The impact of DMTs and HSCT on the histological appearance of "MS-like" CNS pathologies is unknown. Therefore, reporting this and similar cases will improve our awareness and understanding of underlying disease mechanisms.

In our clinical practice, international prognostic score (IPS) comprising of seven parameters has been in use for prognostication of advance stage Hodgkin's lymphoma (HL). Simple scoring system, that can stratify patients and or predict outcome both in early stage and advance stage HL, would be both helpful and practical to apply in daily practice. This is a retrospective study to find out whether recently reported absolute monocyte count (AMC) and absolute lymphocyte : monocyte ratio (LMR) at diagnosis are valid parameters for predicting prognosis of classical Hodgkin lymphoma (cHL) patients treated with ABVD at our center. Among many cut-off values for ALC/AMC ratio reported in literature (1.1, 1.5, 2.1, 2.8, 3.5) we chose the cut off of ≥2.1 as reported in the largest series by Tadmore et al. Data from patients' records were collected after approval by local institutional review board. All studies were performed in accordance with the principles of the Declaration of Helsinki. Patients were included into this study if they had histopathological diagnosis of cHL, no human immunodeficiency virus infection, availability of data on all clinical and laboratory features and treatments given, as well as outcome, and follow-up. Only patients treated with ABVD as initial chemotherapy with or without subsequent radiation therapy were included as this chemotherapy regimen is currently considered the standard of care in North America and at our institution. Response criteria were based on the guidelines from the International Harmonization Project on Lymphoma revised by Cheson et al. We excluded 4 patients with Nodular Lymphocyte Predominant HL(NLPHL), as NLPHL is considered to be a different disease entity. Hence we found 164 patients with cHL treated at King Fahad Medical City, Riyadh from 2006, through July 2015 with ABVD. Out of 164 patients we identified nodular sclerosis 116/164 (70%) and mixed cellularity 31/164 (19%) were the most common. The median age of the patients was 26 years (range, 14-86 years); 70 (41.6%) patients had bulky disease, 84 (52.1%) had extranodal disease; Median IPS was 3; Pre-Treatment ALC median was 1635/ul (range 192-825), AMC median was 841/ul (range 60-9600), and Pre-Treatment ALC/AMC Ratio (LMR) median was 2.168 (range 0.28-19.81). Overall survival was for ALC/AMC Ratio of >=2.1 was 97.5% and 92.8% for ALC/AMC Ratio of <2.1 (p=0.172) indicating some trend for better outcome. This study confirms that L/M ratio has prognostic value in cHL. However we plan to define our own best cut off value by ROC and AUC analysis as ALC/AMC Ratio of ≥2.1 did not discriminate survival advantage clearly in our patients. In addition to geographical and genetic differences, variations in hematology cell counters may be a plausible contributing factor.Table.VariablesNumber(%)Age(yr)<=45140(85.4)> 4524(14.6)GenderMale88(53.7)Female76(46.3)Stage of diseaseEarly15(9.1)Advanced149(90.9)BulkyNo94(57.3)Yes70(42.7)Stage IVNo92(56.1)Yes72(43.9)HistopathologyLymphocyte Rich6(3.7)Classical11(6.7)Mixed Cellularity31(18.9)Nodular Sclerosis116(70.7)ExtranodalNo80(48.8)Yes84(51.2)Albumin<40134(85.4)>=4023(14.6)Hemoglobin<10.559(36.0)>=10.5105(64.0)WBC<15127(77.4)>=1537(22.6)IPS Score05(3.0)134(20.7)242(25.6)342(25.6)432(19.5)57(4.3)62(1.2)ALC<60016(10.3)>=600140(89.7)ALC<0.622(14.1)>=0.6134(85.9)AMC<75070(44.9)>=75086(55.1)ALC/AMC Ratio<2.172(46.2)>=2.184(53.8) Disclosures No relevant conflicts of interest to declare.

Background The role of fluorodeoxyglucose–positron emission tomography/computed tomography (FDG-PET/CT) in indolent lymphoma has been minimally studied. Objective This study aims to assess the value of FDG-PET/CT in predicting the prognosis of indolent lymphoma. Methods We prospectively recruited 42 patients with indolent lymphoma. A total of 2 patients were excluded, and 40 underwent baseline PET/CT and follow-up at various time points. A total of 9 patients were observed only, 7 received 4 doses of rituximab alone, and 24 received chemoimmunotherapy. Metabolic response on follow-up PET/CT was assessed using the maximum standardized uptake value (SUVmax) and Deauville criteria (DC). We aimed to obtain the best SUVmax and DC to predict optimal survival rates, risk stratification, and optimize therapeutic strategies. The mean follow-up from the initial diagnosis was 33.83 months. Results SUVmax <4.35 at interim PET/CT provided the best discrimination, with a progression-free survival (PFS) of 100% and a median survival time of 106.67 months compared with SUVmax ≥4.35 (P=.04), which had a PFS of 43.8% and a median survival time of 50.17 months. This cutoff was also valuable in predicting overall survival at baseline, that is, 100% overall survival with baseline SUVmax <4.35, versus 58.4% for SUVmax ≥4.35 (P=.13). The overall survival of patients with a baseline DC score <3.0 was 100%, with a median overall survival of 106.67 months. Conclusions We demonstrated the utility of PET/CT in indolent lymphomas. SUVmax (<4.35 vs ≥4.35) on interim PET/CT performed best in predicting PFS.

Background: Indolent lymphomas (ind-LYM) are a subset of B-cell lymphomas, characterized by slow growth, protracted course without treatment and a tendency to reoccur after therapy. The management of ind-LYM is varied and evolving. To-date reliable tools for imaging based prognostication and treatment strategies are limited. We explored the utility of serial FDG PET scans (baseline (BL), interim/6 months (INT) end of therapy/1 year (EOT)), in managing ind-LYM). Methods: From an ongoing prospective study, examining the role of PET scan in ind-LYM at our institution, we performed an interim analysis of all patients hitherto enrolled in our study. Patients diagnosed as ind-LYM and having undergone serial PET scans from 2015 to date (N=40, males= 27, females =13) had median age of 59.68 ± 14.5 (28-82 at diagnosis. All PET scans were obtained per accepted protocols. SUVmax and Deauville scores (DS) were obtained from five target lesions. The average of composite SUV (cSUV) and composite Deauville scores (cDS) were computed for each patient. Statistical analyses (using t-test, mean delta change) were performed with the cSUV and cDS. Results: The types of ind-LYM were CLL/SLL (17), Follicular (15), mantle cell (3), marginal zone lymphoma (3), and 1 each of MALT and lymphoplasmacytic lymphoma. The data were analyzed for two arms of the study treatment chemotherapy arm (CHEMO-22/40) and Rituximab + observation arm (OBSR-18/40). At BL, patients on CHEMO had significantly higher cSUV and cDS compared to those who were on OBSR (SUV: 6.99 vs. 4.32 p-value 0.0124; cDS: 4.37 vs 3.71 p-value 0.0075 respectively). Although there was a delta change in the cSUV and cDS in both arms after INT and EOT, both treatment lines showed no significant difference in the SUV mean and DS (p-value: 0.754 and 0.5721, receptively). A 2-tailed T-test was used for delta change of cSUV. BL to INT cSUV was statistically significant (p-valve 0.05) and difference in cSUV was not significant for BL to EOT (p-valve 0.98). Difference in cDS was not significant between BL, INT and EOT. Conclusion: The higher cSUV/cDS at BL for the treatment arm may be due to disease profile at the time of presentation and/or selection bias. At EOT no difference in both estimates were noted. Both arms showed similar trends in delta change from BL-INT-EOT. Our findings suggest that SUV and DS at BL maybe an independent criterion for treatment selection in ind-LYM. Disclosures No relevant conflicts of interest to declare.

BACKGROUND The role of fluorodeoxyglucose–positron emission tomography/computed tomography (FDG-PET/CT) in indolent lymphoma has been minimally studied. OBJECTIVE This study aims to assess the value of FDG-PET/CT in predicting the prognosis of indolent lymphoma. METHODS We prospectively recruited 42 patients with indolent lymphoma. A total of 2 patients were excluded, and 40 underwent baseline PET/CT and follow-up at various time points. A total of 9 patients were observed only, 7 received 4 doses of rituximab alone, and 24 received chemoimmunotherapy. Metabolic response on follow-up PET/CT was assessed using the maximum standardized uptake value (SUVmax) and Deauville criteria (DC). We aimed to obtain the best SUVmax and DC to predict optimal survival rates, risk stratification, and optimize therapeutic strategies. The mean follow-up from the initial diagnosis was 33.83 months. RESULTS SUVmax &lt;4.35 at interim PET/CT provided the best discrimination, with a progression-free survival (PFS) of 100% and a median survival time of 106.67 months compared with SUVmax ≥4.35 (<i>P</i>=.04), which had a PFS of 43.8% and a median survival time of 50.17 months. This cutoff was also valuable in predicting overall survival at baseline, that is, 100% overall survival with baseline SUVmax &lt;4.35, versus 58.4% for SUVmax ≥4.35 (<i>P</i>=.13). The overall survival of patients with a baseline DC score &lt;3.0 was 100%, with a median overall survival of 106.67 months. CONCLUSIONS We demonstrated the utility of PET/CT in indolent lymphomas. SUVmax (&lt;4.35 vs ≥4.35) on interim PET/CT performed best in predicting PFS. CLINICALTRIAL