Clinical and pathologic features of secondary acute promyelocytic leukemia

Abstract

Acute promyelocytic leukemia (APL) is a relatively common form of acute myeloid leukemia (AML) that has an excellent prognosis. In contrast, secondary acute myeloid leukemias, including therapy-related AML and AML with myelodysplasia-related changes, have a relatively poor prognosis. We identified 9 cases of APL at our institution in which there was a history of chemotherapy, radiotherapy, chronic immunosuppression, or antecedent myelodysplastic syndrome. The clinical and pathologic findings in these cases of secondary APL were compared with the clinical and pathologic findings in cases of de novo APL. We found that secondary and de novo APL had abnormal promyelocytes with similar morphologic and immunophenotypic features, comparable cytogenetic findings, comparable rates of FMS-like tyrosine kinase mutations, and similar rates of recurrent disease and death. These data suggest that secondary APL is similar to de novo APL and, thus, should be considered distinct from other secondary acute myeloid neoplasms.

Figure 1

The abnormal promyelocytes in de novo acute promyelocytic leukemia (APL; A) have an immunophenotype similar to that of the abnormal promyelocytes in secondary APL (B). The cases of secondary APL include therapy-related APL and APL arising in a patient with a history of myelodysplastic syndrome.

Image 1

The abnormal promyelocytes in therapy-related acute promyelocytic leukemia (APL), chronic immunosuppressive therapy–related APL, and myelodysplastic syndrome (MDS)-related APL have morphologic features similar to those of the atypical promyelocytes in de novo APL. Representative aspirates/touch preparations (modified Wright-Giemsa, ×100).

Image 2

Representative flow cytometry plots from therapy-related acute promyelocytic leukemia (APL), subtype M3h (A); chronic immunosuppressive therapy–related APL, subtype M3v (B); and myelodysplastic syndrome–related APL, subtype M3v (C). Background autofluorescence from isotypic controls is shown in green. FITC, fluorescein isothiocyanate; M3h, hypergranular variant; M3v, microgranular variant; PE, phycoerythrin; PerCP, peridinin-chlorophyll protein; SSC, side scatter.