Myelodysplastic/Myeloproliferative Neoplasms with Isolated Isochromosome 17q
Definition
- Unclassifiable myeldysplastic/myeloproliferative neoplasm (MDS/MPN-U) with isolated isochromosome 17q
Note
- This is a newly recognized entity not specifically categorized in the WHO 2008 edition
Diagnostic Criteria
-
Meets criteria for MDS/MPN-U
- Must have both myelodysplastic and myeloproliferative features
- Must not satisfy criteria for any defined myeloid neoplasm
- Demonstrates isochromosome 17q as the sole or primary cytogenetic abnormality
- Molecular pathology evidence of other mutations occasionally seen
- Characteristic features
- Pseudo-Pelger-Huet-like neutrophils
- Micromegakaryocytic hyperplasia
- Marrow hypercellularity, fibrosis, and osteosclerosis
- Increased marrow blasts (definitionally <20% in this category)
- Short overall survival
- High risk of leukemic transformation
Differential Diagnosis
- This is a diagnosis of exclusion
- Isochromosome 17 may be seen as a primary or secondary cytogenetic abnormality in other myeloid neoplasms, which must first be excluded
Dita Gratzinger MD PhD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting: 11/6/11
