Clinical and laboratory features:
(1) adult (from 32 to 74 years old) with pancytopenia
(2) serum vitamin B12 levels that were initially within normal limits
(3) dysplastic cytologic features seen in the bone marrow
(4) elevated serum LDH and elevated serum total bilirubin, suggesting hemolysis
(5) normal bone marrow karyotype
If serial measurement of the vitamin B12 was performed, then a downward trend or fluctuation in levels was observed.
Some patients had an elevated methylmalonic acid level but most did not.
Some patients patients had antiparietal cell and/or anti-intrinsic factor antibodies.
A patient with pseudo-myelodysplasia will show a correction in the complete blood count after a 1-2 week course of parenteral vitamin B12. The response was defined as all of the following:
(1) hemoglobin > 10 g/dL
(2) increase in the absolute granulocyte count by > 1,500 per µL
(3) increase in the platelet count by > 100,000 per µL
