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.
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.
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.
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.