Lymphomatous presentation of childhood acute lymphoblastic leukemia. A subgroup at high risk of early treatment failure.

Multivariate analyses of the clinical course of 1537 children with acute lymphoblastic leukemia (ALL) identified a subgroup which experienced short remission duration and a high incidence of extramedullary relapse. The patients differed from other ALL patients by the presence at diagnosis of two or more of a constellation of clinical and laboratory features: organomegaly or mass disease, E-rosette positivity, hemoglobin level greater than 10 g/dl, leukocyte count greater than 50,000/microliters, male predominance, and older age. This type of presentation of ALL is referred to as the "lymphoma syndrome" (LS) since such patients exhibit a pattern of several clinical and laboratory features which were observed repeatedly but in differing combinations, and some of which clinically resemble lymphoma. A subsequent database from 2231 patients was analyzed. Patients with a mediastinal mass, massive splenomegaly, or massive adenopathy, alone or in combination, had a worse outcome when the patient also had either leukocytosis, E-rosette-positive lymphoblasts, or a normal or near normal hemoglobin (Hb) level at diagnosis. Similarly, the above three laboratory features alone or in combination did not predict less than 40% disease-free survival (DFS) unless they were accompanied by at least one of the clinical features of mass disease. When at least one clinical feature and at least one laboratory feature were present, the overall DFS was 36% 6 years after diagnosis versus 64% for all other patients. The association of these features with poor prognosis remained significant after adjusting for the level of leukocyte count at diagnosis, age at diagnosis, and sex of the patients. Patients with this recurrent syndrome of features do not represent a homogeneous biologic entity but they constitute a subgroup of patients with ALL having a high risk of treatment failure using current therapies, including failure to achieve remission, early relapse, and increased frequency of relapse in extramedullary sites. They deserve early recognition at diagnosis and selection of treatment strategies appropriate for very high risk ALL.