Concurrent inflammatory bowel disease and myelodysplastic syndrome: report of nine new cases and a review of the literature.

Nine patients with concurrent myelodysplastic syndrome (MDS) and inflammatory bowel disease (IBD) were examined. Median age at diagnosis of these patients was similar to the usual age of patients at diagnosis of IBD only. There was a strong predominance of Crohn's disease (seven of nine cases), with an unusually high frequency of colorectal involvement (five of nine cases). Inflammatory bowel disease was diagnosed first in one patient, MDS first in five patients, and both diseases were diagnosed simultaneously in three patients. All patients had moderate or severe anemia. The prognosis of IBD was determined by MDS. These observations suggest that there is an unclear common pathogenesis of IBD and MDS and, consequently that patients with IBD and anemia of non-obvious origin should be evaluated for the presence of MDS.