Apart from challenges in defining IBMFS-associated CMMT, the classification and grading of this disorder presents another challenge, because some of the clinical and biological features that are used to characterize de novo CMMT (e.g. prominent dysplasia and increased marrow cellularity) are less common in IBMFS-associated CMMT. In 2002 we developed the "Category Cytology Cytogenetics" (CCC) classification for pediatric MDS, which aimed to address aspects not only of de novo MDS, but also of therapy-related and IBMFS-associated MDS.11