Case Discussion

[dralaa]

A 78-year-old man complains of increasing fatigue and bone pain, especially around the knees and ankles. He has a long-standing anemia with a hemoglobin of 9 to 10 g/dL and MCV of 102. He had not responded to therapeutic trials of iron and vitamin B12, but had been symptomatically stable until the past month. Examination reveals pallor and spleen tip just palpable at the left costal margin. CBC reveals hemoglobin of 8.2 g/dL, but for the first time his platelet count is low (15,000); the white blood cell
count is 14,000.

[dralaa]

The answer is b. The patient has probably
had myelodysplastic syndrome (MDS) for years. This is a common cause of
anemia with mild macrocytosis in the elderly. Some of these patients will
transform into acute myeloid leukemia. The leukemic cells can expand the
marrow and cause diffuse bone pain (especially over the sternum and
around the knees). Although 20% of patients with MDS can have mild
splenomegaly, the newly detected spleen tip and the rapidly worsening
pancytopenia suggest that leukemic cells are squeezing out the normal
hematopoietic cells. Patients with secondary AML (i.e., AML that arises
from a preexisting hematopoietic disease) have a grave prognosis and
respond poorly to combination chemotherapy