Cunha KC, Oliveira MC, Gomes AC, Castro LP, Viana MB n = 1), bone marrow involvement (≥ 25% L3-morphology blasts; n = 2), and an erroneous initial diagnosis (n = 1). In this latter case, the patient was initially diagnosed as BL on morphological grounds. After complete immunophenotyping characterization, the diagnosis was changed to lymphoblastic B-cell lymphoma. The medical records were reviewed to collect demographic data (age, gender), clinical data (medical history, physical examination, nutritional status, clinical presentation), diagnostic procedures (imaging studies, bone marrow aspiration, cerebrospinal fluid - CSF analysis), staging, laboratory data (lactate dehydrogenase - LDH levels, blood counts, serum electrolytes, liver and kidney profile), treatment, and outcome. Diagnosis was made by incisional or excisional biopsy, or cytological examination of pleural or abdominal effusions. Karyotype studies were not available at the time. All the diagnoses were confirmed according to the morphologic and immunohistochemistry criteria defined by the World Health Organization (WHO) classification(2). Immunohistochemistry was performed using monoclonal antibodies CD20, CD10, CD79a, CD30, CD3, CD15, TdT, CD45, and CD45RO. Confirmation of B-cell lineage by immunophenotyping required 50% or more neoplastic cells to express CD45, CD10, CD20, and CD79a. Pleural or abdominal effusions were examined by flow cytometry. Clinical staging was based on the St. Jude Children’s Research Hospital staging system(10). Central nervous system (CNS) disease was diagnosed by the presence of morphologically identifiable lymphoma cells (regardless of quantity) in CSF, an intracerebral mass or cranial nerve palsy not caused by an extracranial mass. To evaluate malnutrition, Z-scores of weight for age (WAZ) and height for age (HAZ) were used(11). The chosen cutoff point to discriminate undernourished from well-nourished status was a Z-score of less than 1.28 (10th percentile). Although less specific, it is more sensitive than the cutoff point of Z = -2. The variables studied for a possible association with prognosis were gender, age, staging, nutritional status, serum LDH and kidney function. Treatment Patients admitted between 1981 and 1987 were treated according to the modified LSA2L2protocol of the Memorial Sloan- Kettering Cancer Center(12). After 1987, the patients were treated with a BFM-83-based protocol (Berlin-Frankfurt-Münster)(13). The first cycle of treatment was modified in patients with severe clinical events at diagnosis, such as a high tumor burden associated with pleural and peritoneal effusions, tumor lysis syndrome and sepsis. At diagnosis, all patients were vigorously hydrated and alkalized with NaHCO3 associated with allopurinol. Treatment of parasitic infection was performed before the beginning of chemotherapy. Response criteria Complete remission (CR) was defined as the disappearance of all tumor masses confirmed by clinical examination and imaging investigations, when necessary one month after therapy. After the end of treatment, the patients were followed at 30-day 362 intervals during the first year, at 60-day intervals during the second year and at 3- to 6-month intervals up to five years. Progression of the local tumor was defined if the tumor site showed no decrease in size after the initiation of chemotherapy. Relapse was defined as the recurrence of lymphoma with the same histological or immunophenotypic features as the initial one at any site after CR was achieved. Local relapse was diagnosed when it involved a previously involved site (except bone marrow and CSF). Statistical analysis The time limit for the current study was the end of March 2008. The overall survival (OS) was defined as the time from diagnosis to date of death due to any cause or date of last follow-up contact for patients who were alive. The OS was analyzed using the Kaplan–Meier method. The analysis of prognostic factors was based on the OS and the comparison of curves by the log-rank test(14). Data are reported as medians and interquartile range (IQ) or means and standard deviation (SD), when appropriate. The Mann-Whitney or Kruskal-Wallis tests were used to compare nonparametric continuous variables. Dichotomous variables were compared by the two-tailed chi-square test or Fisher exact test. The level of significance was set for a p-value ≤ 0.05. Statistical analysis was performed using the SPSS software (version 10.0). EPI INFO 6.0 was used to assess the scores of height for age (HAZ) and weight for age (WAZ). Ethical issues The study was approved by the Research Ethics Committee of UFMG. Written informed consent was obtained from the guardians of the patients and, when appropriate, from the patients themselves, according to the Helsinki Declaration. Results Patient characteristics The median age at diagnosis was 4.7 years (range: 11.5 months to 13.2 years). There was a predominance of males (2.8:1). Diagnosis was based on cytological examination of abdominal effusions in three patients (6.7%), pleural effusions in two patients (4.4%), and on tumor biopsies for the other cases. Immunohistochemistry was performed in 29 patients. For one patient immunohistochemistry was inconclusive because of technical problems with the fixing of samples. Malnutrition, as defined by WAZ and HAZ, was present in one third and one fifth of the patients, respectively. The clinical and demographic characteristics of the patients are shown in Table 1. Abdominal tumors, occurring in 30 patients (66.7%), were the most common presenting feature. Abdominal involvement was associated with disease at other sites, such as pleural and abdominal effusions, and peripheral lymphadenopathy. Mediastinal involvement and facial involvement were observed in three patients (6.7%) and six patients (13.3%), respectively. Of these latter children, jaw tumors were observed in three patients and tumors located in the nasopharynx in the other three. Other involved organs included peripheral lymph nodes (two patients) and CNS (one patient). Three patients had Rev Bras Hematol Hemoter. 2012;34(5):361-6