Association between myelodysplastic syndromes and inflammatory bowel diseases. Report of seven new cases and review of the literature.

We report seven patients with both myelodysplastic syndrome (MDS) and inflammatory bowel disease (IBD): Crohn's disease in six cases, ulcerative colitis in one case. We describe their characteristics, and those of 10 previously published similar cases are presented here. Median age at diagnosis of IBD (61 years) was high, as compared to the usual age at diagnosis of IBD. IBD was diagnosed first in nine cases, MDS first in one patient, and both diseases were diagnosed simultaneously in seven cases. Concerning IBD, there was a strong predominance of Crohn's disease (15/17 cases), with an unusually high frequency of colonic involvement (11/15 cases). MDS, in 12/17 cases, showed no excess of marrow blasts. Cytogenetic analysis was abnormal in five of the 13 evaluable cases. These observations suggest that the association between MDS and IBD may not be fortuitous in some cases, and that, in particular, patients with IBD and anemia of nonobvious origin should be evaluated for MDS. The pathogenesis of those associations, however, remains unclear.