Patients With a History of Chemotherapy and Isolated del(20q) With Minimal Myelodysplasia Have an Indolent Course.

OBJECTIVES: Isolated deletion (20q) is relatively common in myeloid neoplasms and has been rarely reported in cases of therapy-related myelodysplastic syndrome (MDS). Our aim was to characterize cases of isolated del(20q) in bone marrow biopsy specimens from patients with a history of chemotherapy with morphologic findings insufficient for a diagnosis of MDS.

METHODS: In this retrospective study from one institution, we identified 22 patients with isolated del(20q) and no or minimal dysplasia and evaluated clinical and pathologic characteristics.

RESULTS: Eleven of the patients had a history of chemotherapy for mostly lymphoproliferative disorders. There were no statistically significant differences in peripheral blood or bone marrow features between patients with a history of chemotherapy and those without. Three patients with a history of chemotherapy had died at last follow-up; cause of death was recurrent nonmyeloid neoplasm. None of the patients with a history of chemotherapy subsequently developed a high-grade myeloid neoplasm, whereas one of the patients who had not received prior chemotherapy developed refractory anemia with excess blasts 2.

CONCLUSIONS: The presence of del(20q) as an isolated bone marrow cytogenetic abnormality in the absence of morphologic findings sufficient for a diagnosis of acute myeloid leukemia, myeloproliferative neoplasm, or MDS portends an indolent clinical course, regardless of previous exposure to chemotherapy.