Mediastinal nonlymphoblastic lymphomas in children: a clinicopathologic study.

The records of 25 pediatric patients with mediastinal nonlymphoblastic lymphoma (NLBL) were reviewed. These patients comprise approximately 5% of all patients with non-Hodgkin's lymphoma (NHL) in the pediatric age group. There were 15 females and ten males. The median age was 13.5 years (range, 2 to 19). Most patients presented with symptoms attributable to a large mediastinal mass, and superior vena cava syndrome was a common feature. Disease was localized to the supradiaphragmatic area in 17 patients (71%) at diagnosis. Pathologic review revealed 22 of these lymphomas to be diffuse histiocytic type in the Rappaport classification, and 20 were large-cell immunoblastic type in the Working Formulation. Treatment regimens were not uniform, but included multiagent chemotherapy in 23 patients and radiation to the mediastinum in 20 patients. Twenty-three patients (92%) attained a complete remission (CR). Of these, 17 (74%) remain disease-free 13 to 65 months from diagnosis (median, 43 months). No CNS relapses have been observed. Mediastinal NLBL in the pediatric age group has distinctive clinicopathologic features that warrant special consideration in the design of treatment protocols.