Constitutional trisomy 8 mosaicism with myelodysplastic syndrome complicated by intestinal Behcet disease and antithrombin III deficiency.

Trisomy 8 is the most common acquired chromosomal abnormality associated with myeloid malignancy. As a constitutional trisomy 8 mosaicism (T8M), it exhibits an extremely variable phenotype. In addition, Behcet disease (BD) has been reported as an unusual complication of myelodysplastic syndrome (MDS). To our knowledge, 12 case reports of various hematologic malignancies in patients with T8M and 18 case reports of MDS with acquired trisomy 8 complicated by BD have been published to date. We report a case of constitutional T8M with MDS complicated by intestinal BD and antithrombin III deficiency.