Myelodysplastic syndrome, unclassifiable
Tumours of haematopoietic and lymphoid tissues
Myelodysplastic syndrome, unclassifiable (MDS-U) is a subtype of MDS which initially lacks findings appropriate for classification into any other MDS category.
There are no specific morphological findings. The diagnosis of myelodysplastic syndrome, unclassifiable, can be made in the following instances:
1. Patients with the findings of refractory cytopenia with unilineage dysplasia (RCUD) or refractory cytopenia with multilineage dysplasia (RCMD) but with 1% blasts in the PB qualify for MDS-U
Knipp S, Strupp C, Gattermann N, Hildebrandt B, Schapira M, Giagounidis A, Aul C, Haas R, Germing U (2008)
Presence of peripheral blasts in refractory anemia and refractory cytopenia with multilineage dysplasia predicts an unfavourable outcome.
Leuk Res 32: 33-7
2. Cases of MDS with unilineage dysplasia which are associated with pancytopenia. In contrast, the RCUD category only allows for a single cytopenia or bi-cytopenia.
3. Patients with persistent cytopenia(s) with 1% or fewer blasts in the blood and fewer than 5% in the BM, unequivocal dysplasia (Table 5.03). in less than 10% of the cells in one or more myeloid lineages, and who have cytogenetic abnormalities considered as presumptive evidence of MDS (Table 5.04) are placed in this category. MDS-U patients should be carefully followed for evidence of evolution to a more specific MDS type.