Introduction.
Rare, indolent, and likely due to stepwise accumulation of molecular
mutations, MDS/MPN overlap syndrome with ring sideroblasts and
thrombocytosis (MDS/MPN-RS-T) is a myeloid neoplasm associated with
dysplasia and cytopenias as well as myeloproliferation and
cytoses1. Therefore, in this entity, driver mutations
of JAK2 V617F but also CALR and MPL W515 have been
attributed to the proliferative features whereas the presence of ring
sideroblasts, dyserythropoiesis and cytopenias are chiefly associated
with SF3B1 (K700E) or other similar mutations2. Previously being a provisional entity in the 2008 iteration of WHO,
this disorder is now fully characterized requiring persistent
thrombocytosis (> 450 x 109/L), anemia
with erythroid /multilineage dysplasia, ≥15% ring sideroblasts,
<1% blasts in the peripheral blood and <5% blasts
in the bone marrow. Other diagnostic requirements include the presence
of SF3B1 mutation and lack of reactive causes of ring
sideroblasts, diagnosis of other myeloproliferative or myelodysplastic
entities and absence of certain gene rearrangements diagnostic of other
myeloid neoplasms (i.e. BCR-ABl1, PDGFRA , PDGFRB ,FGFR1 ,PCM1-JAK2, t(3;3) (q21q26), inv (3)(q21q26) or del
(5q) (MDS with thrombocytosis) )1 . Here we describe a
case of an elderly patient with hematomas, and critical thrombocytosis
(initially suspect for acquired von Willebrand disease) who was
diagnosed with MDS/MPN-RS-T.