Bloom's syndrome complicated by myelodysplastic syndrome and multiple neoplasia.

The patient, a Japanese male born to a highly consanguineous family, was diagnosed as Bloom's syndrome at the age of 33 when he presented with diabetes mellitus and refractory anemia with excess blasts. Chromosome abnormalities of bone marrow cells included 5q-, -7/7q-, and unusual translocations. During the ensuing years, he developed squamous cell carcinoma of the external auditory meatus, adenocarcinoma of the colon, and squamous cell carcinoma of the tonsil. The patient died of pneumonia at the age of 38. Autopsy revealed intestinal polyposis and hemochromatosis secondary to massive blood transfusions.