Myeloblastoma with an 8;21 chromosome translocation in acute myeloblastic leukemia.

An 8;21 chromosome translocation was found in cells from myeloblastomas of two acute myeloblastic leukemia (AML) patients. In one patient, a sudden onset of paraplegia, which was caused by an epidural myeloblastoma in the thoracic vertebral canal, was the initial symptom of the disease and that of the first relapse. In the other, myeloblastomas, which occurred in the breasts during a hematologic remission, heralded the first relapse. Karyotypes of tumor cells obtained from both patients showed the t(8;21) and additional chromosome abnormalities. These findings, together with earlier experience and reports in the literature, indicate that myeloblastoma may be unique to the 8;21 translocation, and that certain chromosomal abnormalities additional to the t(8;21) may be necessary for the tumor formation.