Deletion of chromosome 20q associated with hypereosinophilic syndrome: A report of two cases

Deletion of the long arm of chromosome 20—del(20q)—is commonly associated with myeloid malignancies, in particular with myeloproliferative disorders (MPD), myelodysplastic syndrome (MDS), and acute myelogenous leukemia (AML). Its association with the hypereosinophilic syndrome (HES) had never been reported. In the present study we describe two patients with long-standing hypereosinophilia and features of atypical MPD or MDS carrying a del(20q) as a constant and isolated chromosomal abnormality. One patient, with an aggressive clinical course, died within 2 years, despite several lines of treatment. The other patient had a more indolent course consistent with that of an atypical MDS with eosinophilia.