Non-Hodgkin's lymphomas in children.

In children, non-Hodgkin's lymphoma (NHL) accounts for 10% of all malignancies and are consistently high-grade. They can be divided into three histologic categories, namely Burkitt's lymphoma (BL), lymphoblastic lymphoma (LL), and large cell lymphoma. The primary arises in the abdomen, mediastinum, or neck. Diagnosis and management should be carried out in a pediatric oncology unit, and should be done on an emergency basis because of the fast growth rate of NHL. A small number of initial investigations allow to classify NHLs according to the Saint-Jude Hospital (Memphis) scheme. Two bone marrow smears and a lumbar puncture should be done before treatment initiation to look for evidence of stage IV disease, defined as bone marrow and/or neuromeningeal involvement. The mainstay of management is combination chemotherapy, which should be short (3.5-6 months) and intensive in Burkitt's lymphoma, and prolonged (18-24 months), intensive, and sequential in LL. Radiation therapy with curative intent is used only in LLs with neuromeningeal involvement. Cure rates with current chemotherapy regimens are 90% in Burkitt's lymphoma and 80% in LLs. Recurrences of Burkitt's lymphoma occur within one year of diagnosis, whereas those of LLs can occur as late as four years after diagnosis.