BACKGROUND AND AIMS: There is scarce information about pediatric lymphoblastic lymphoma (LLy) in low and middle-income countries. We describe the clinical characteristics, treatment and outcome of a cohort of children and adolescents with LLy in Latin America (LA). METHODS: Retrospective study analyzing pediatric patients with LLy in 10 institutions of the St. Jude Global Alliance from nine LA countries between 2007 and 2017. RESULTS: One-hundred and twenty-six patients were included. Sixty (47.6%) had T-LLy, 49 (38.9%) B-LLy and in 17 (13.5%) the immunophenotype was unknown. Ninety-seven (77%) presented with stage III/IV disease, and 42 (33.3%) in critical conditions. In 30 cases (23.8%), the results of pathology diagnosis exceeded 15 days from biopsy, and 23 patients (18%) required a review at another institution. The EFS and OS at 5 years were 73% (SE 0.047) and 78% (SE 0.0435), respectively. Five-year abandonment-sensitive EFS and OS were 65% (SE 0.0477) and 70% (SE 0.0459), respectively. Events included relapse/progression (n=22), refractory disease (n =1) abandonment (n=11), induction death (n=4), death in complete remission (n=4), and second malignancies (n=1). CONCLUSIONS: A balanced proportion of LLy-T and B phenotypes was observed. Diagnosis was a challenge. Most of the patients presented with high-risk disease, and many in critical conditions. Toxic deaths and abandonment represented nearly half of the events. Improvements in diagnosis, supportive measures and follow up are imperative to improve the outcomes of pediatric LLy in Latin America.

Introduction: The risk of relapse in retinoblastoma is currently determined by the presence of high-risk histopathologic factors in the enucleated eye. However, the probability of developing metastatic disease is heterogeneous among these patients. Evaluating a biological marker to identify high-risk patients could be useful in clinical setting. This study aims to evaluate whether the expression of TFF1, a surrogate for subtype 2 retinoblastoma, is a prognostic marker for relapse and death. Methods: This multicenter cohort study included 273 patients, 48 of whom had extraocular disease. Immunohistochemical staining were performed for CRX, ARR3, TFF1 and Ki67. Tumors were classified as histological subtype 1 (HS1) if they had low or no expression of TFF1 (quick score (QS) ≤ 50) and as histological subtype 2 (HS2) if they expressed TFF1 diffusely (QS > 50). We studied the association between HS classification and outcome. Results: Of 273 patients, 35.9% were classified as HS1, 59.3% as HS2 and 4.8% were not evaluable. In multivariate analysis, patients with HS2 tumors had a higher probability of relapse and death than those with HS1 ( P < 0.0001 and P = 0.00020, respectively). We identified a higher-risk subgroup among HS2 tumors, presenting non-mutually exclusive expression of ARR3 and TFF1 and had an increased risk of relapse and death compared to tumors that displayed mutually exclusive expression ( P = 0.012 and P = 0.027, respectively). Conclusions: Expression of TFF1, especially when it is not-mutually exclusive with ARR3, is an independent prognostic marker of poor outcome in retinoblastoma.