Bone marrow neoplastic
Bone marrow - neoplastic myeloid
Myelodysplastic syndromes / neoplasms (MDS)
MDS unclassifiable
Author: Nikhil Sangle, M.D.
Last author update: 1 August 2011
Last staff update: 22 September 2023
Copyright: 2002-2024, PathologyOutlines.com, Inc.
PubMed Search: MDS unclassifiable
Table of Contents
Definition / general | Case reports | Microscopic (histologic) images | Differential diagnosisCite this page: Sangle N. MDS unclassifiable. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/myeloproliferativeMDSNOS.html. Accessed November 30th, 2024.
Definition / general
Myelodysplastic syndrome, unclassifiable (MDS-U) diagnosis can be made in 3 instances:
- Unequivocal dysplasia < 10% in one or more lineage, with cytogenetic abnormalities presumptive of MDS, and < 1% blasts in peripheral blood, 5% blasts in bone marrow
- Refractory anemia or refractory cytopenia with multilineage dysplasia with 1% blasts in peripheral blood
- Unilineage dysplasia with pancytopenia
- Cases can be reclassified into specific subtypes later if characteristic features develop
- Some cases are associated with prior aplastic anemia and monosomy 7 (Am J Clin Pathol 2006;126:925)
- Myelofibrosis: when present, often is difficult to obtain bone marrow aspirate; patients often have pancytopenia with dysplasia in 3 lineages; CD34 staining helps identify blast population
Case reports
- 82 year old man with moderate thrombocytopenia (University of Pittsburgh Case #520)
Microscopic (histologic) images
AFIP images
Pancytopenia, abnormally bilobed nuclei in granulocytes
Marked increase in megakaryocytes
Erythroid hyperplasia
Large erythroid precursors
Hypercellular marrow with marked fibrosis
Cluster of large megakaryocytes
Marked reduction in megakaryocytes
Recurrence with increased marrow cellularity
Images hosted on other servers:
Megakaryocyte clustering and hyperlobulated forms (figs 2 / 3)
Differential diagnosis
- Acute panmyelosis with myelofibrosis (20% or more blasts),
- AML-M7 (20% or more blasts),
- Chronic idiopathic myelofibrosis (usually marked splenomegaly, no dysplasia)
