Ki-1 lymphoma in two children.

Childhood Ki-1 lymphoma is rarely reported in Taiwan. We present two 8-year-old girls with Ki-1 lymphoma diagnosed and treated at the National Taiwan University Hospital. The first patient presented with a neck mass with hepatosplenomegaly. The second patient initially presented with joint pain and pathologic fracture; she was later found to have bone marrow involvement. Histologic studies of both tumors revealed bizarre large cells with pleomorphic nuclei and prominent nucleoli. All these cells were immunolabeled with monoclonal antibody Ki-1. The two patients received different polyregime chemotherapy protocols followed by bone marrow transplantation (BMT); patient 1 had autologous BMT and patient 2 had allogeneic BMT. In addition, local radiotherapy and retinoic acid were tried for patient 1 but she responded poorly and died 2 years after presentation. In patient 2, although bone marrow was initially involved, allogeneic BMT was performed smoothly after tumor loading was reduced and the patient was in remission at last follow-up, 26 months after presentation. Ki-1 lymphoma in children is characterized by clinical presentations, and histologic and immunologic findings. Aggressive polyregime chemotherapy and bone marrow transplantation are treatments for this disease.