Nuances of Morphology in Myelodysplastic Diseases in the Age of Molecular Diagnostics

Morphologic dysplasia is an important factor in diagnosis of myelodysplastic syndrome (MDS). However, the role of dysplasia is changing as new molecular genetic and genomic technologies take a more prominent place in diagnosis. This review discusses the role of morphology in the diagnosis of MDS and its interactions with cytogenetic and molecular testing. Recent changes in diagnostic criteria have attempted to standardize approaches to morphologic diagnosis of MDS, recognizing significant inter-observer variability in assessment of dysplasia. Definitive correlates between cytogenetic/molecular and morphologic findings have been described in only a small set of cases. However, these genetic and morphologic tools do play a complementary role in the diagnosis of both MDS and other myeloid neoplasms. Diagnosis of MDS requires a multi-factorial approach, utilizing both traditional morphologic as well as newer molecular genetic techniques. Understanding these tools, and the interplay between them, is crucial in the modern diagnosis of myeloid neoplasms.