Preleukemic syndromes.

Acute nonlymphocytic leukemia (ANLL) is preceded by a hematologic illness representing the "preclinical" stages of the disease in many patients. This "preclinical stage" or preleukemic stage is difficult to recognize by conventional hematologic morphologic techniques. A prospective study was carried out to determine whether cytogenetic studies would be helpful in the recognition of preleukemic states and whether the presence of cytogenetic abnormalities would have prognostic significance. A study of 284 patients with suspected preleukemia has yielded 62 patients with progression to overt ANLL. Cytogenetic abnormalities were found in 30% of suspected preleukemic patients, whereas 53% of the patients progressing to acute leukemia had cytogenetic abnormalities. These studies show that the presence of cytogenetic abnormalities aid in the recognition of preleukemia but are not specific for early leukemia. Patients with cytogenetic abnormalities are more likely to develop overt ANLL. Banded chromosome studies demonstrated cytogenetic abnormalities in the preleukemic phase in 13 of 26 patients. A variety of clonal chromosomal abnormalities were observed.