Double minute chromosomes. A bone marrow indicator of neuroblastoma metastasis and relapse: two case reports.

Two cases of childhood neuroblastoma are presented. Case 1 was diagnosed as Stage IV with metastasis to the bone marrow. During remission, histologic studies of bone marrow aspirate and biopsy showed a normocellular marrow with no evidence of malignant cells. Concurrent cytogenetic studies of the bone marrow showed the majority of the cells to contain double minute chromosomes (DM). The chromosome findings indicated the presence of neuroblastoma cells in the marrow prior to histologic evidence of relapse. Case 2 was diagnosed as Stage I neuroblastoma with no metastasis to the bone marrow. Subsequent cytogenetic studies showed DM present in a small number of cells and a deletion of chromosome 1 (1p-) in a single cell. The chromosome findings indicated an advanced stage of malignancy which was not evident with histologic techniques. These findings suggest that cytogenetic analysis of bone marrow can be a valuable aid to the early diagnosis, prognosis, and treatment of neuroblastoma.