Unclassifiable myelodysplasia (MDS-U) refers to a form of myelodysplasia that cannot be classified into one of the main categories. It consists of 3 subtypes which can have a different prognosis.
MDS-U BL
(1) refractory cytopenia
(2) uni- or multi-lineage dysplasia
(3) 1% blasts in the peripheral blood
(4) may have isolated del(5q)
MDS-U Pan
(1) pancytopenia (hemoglobin < 10 g/dL; platelet count < 100,000 per µL; absolute neutrophil count < 1,800 per µL)
(2) unilineage dysplasia
MDS-U CG
(1) persistent cytopenia (> 6 months)
(2) less than 10% dysplastic cells in any lineage
(3) less than 5% bone marrow blasts
(4) less than 1% blasts in the peripheral blood
(5) any MDS-defining cytogenetic abnormalities
Median survival for MDS-U BL was 1.9 years.
MDS-U Pan and MDS-UG had an indolent course with most show a survival > 12 yeras.
