Clinical History:
- A 5-year-old girl has become increasingly listless for the past 2 months. Her mother notes that, whenever she falls or bumps into anything, a big bruise forms. For the past 2 days she has had a high fever. On physical examination vital signs include temperature 39.3 C, pulse 90/minute, respirations 21/minute, and blood pressure 95/60 mm Hg. Laboratory studies show Hgb 9.8 g/dL, Hct 29.6%, MCV 95 fL, platelet count 74,000/microliter, and WBC count 2,300 with differential count 23 segs, 15 bands, 12 monos, 44 lymphs, 5 eos, and 1 baso. A bone marrow biopsy is performed. Her peripheral blood smear is shown.
- What type of white blood cells are present?
The white blood cells present are predominantly lymphoblasts. The biopsy on microscopic examination shows replacement by primitive cells that have large nuclei with delicate chromatin and indistinct nucleoli. There is scanty cytoplasm with no granules and no Auer rods. These cells mark for CD10 (CALLA) antigen, as well as the typical B cell markers (CD19 and CD20).
- What is the most likely diagnosis?
The most likely diagnosis is acute lymphocytic leukemia
(ALL). This is an example of an "aleukemic" leukemia in which few circulating blasts are present, yielding a leukopenia. The morphologic appearance of the blasts suggests a neoplastic process, and a bone marrow biopsy would be done.
- What is the most likely outcome of this child's disease with standard
therapy?
The most likely outcome of this child's disease with standard therapy is good--a >90% chance for complete remission following chemotherapy.
- What other test could be helpful in distinguishing the nature of the cells in this case?
A TDT (terminal deoxyribonucleotidyl transferase) test is positive in cases of lymphoid leukemias.
|
|
