Paroxysmal nocturnal hemoglobinuria clone in a case of myelodysplastic syndrome rapidly progressing to acute leukemia.

Myelodysplastic syndrome (MDS) comprises a group of stem cell disorders with considerable clinical and morphological heterogeneity. We report a case of MDS in a middle-aged male with clinical features of sepsis, dysplastic neutrophils and 6% blasts on bone marrow aspirate. A clone of neutrophils with deficient expression of CD16, CD55 and CD59 was found. A diagnosis of MDS with excess blasts with co-existent paroxysmal nocturnal hemoglobinuria (PNH) was made. Within a fortnight, the patient progressed to acute myeloid leukemia. We are reporting this unusual case of MDS displaying a sizeable clone of dysplastic neutrophils deficient in glycosyl phosphatidyl inositol anchored proteins, highlighting a common origin of PNH and leukemic clone.