Contributed by Beth Z Clark, MD, Sara A Monaghan, M.D., Sarangarajan Ranganathan, MD and Lydia Contis, MD
Published on line in January 2006
The patient is a 19 year-old female with no significant medical history who presented with a palpable, tender nodule in her left axilla and left-sided rib pain. The patient denied headache, fevers, chills, night sweats, and recent weight loss. She also denied sick contacts, shortness of breath, and recent bruising or bleeding.
Complete blood count with differential count obtained at the time of initial evaluation revealed:
|Atypical Lymphs||1.25 X10e+09/L|
Based on the lymphadenopathy and peripheral blood findings, the patient underwent bone marrow evaluation. At the time of bone marrow evaluation, the peripheral blood findings were similar to those above, but in addition, rare blast-like cells were identified.
The bone marrow aspirate smears were cellular, and showed heterogeneous populations. Based on the differential count, the percentage of bands was moderately increased (24.4%, range 9.0-18.0%), the percentage of neutrophils was slightly increased (15%, range 7.0-14.0%), the percentage of blasts was normal (1%), and the myeloid:erythroid ratio was at the upper limit of normal (3.2, range: 1.5-3.3). Morphologically, granulocytic and erythroid precursors showed progressive maturation with slight megaloblastoid changes. Although the patient did have a peripheral blood eosinophilia, there was no increase in eosinophilic precursors in the bone marrow aspirate differential count. The megakaryocytes were well represented, and many were small with hypolobated and monolobated nuclei. An iron stain was negative.
The marrow biopsy was nearly 100% cellular, and highlighted the morphologically abnormal megakaryocytes. A reticulin stain showed moderate reticulin fibrosis. A CD34 immunohistochemical stain showed no overt increase in CD34+ blasts, and TdT showed no increase in TdT+ lymphoblasts.
Flow cytometric immunophenotypic studies performed on the bone marrow revealed heterogeneous cellular populations, with no increase in CD34 positive blasts. There was a population of cells comprising approximately 2% of events and expressing TdT, but these cells were not identifiable as lymphoblasts of either T-cell or B-cell lineage.
Cytogenetics studies performed on the bone marrow aspirate showed the following abnormality in 20 of 20 cells examined:
The patient then underwent an excisional biopsy of the palpable axillary nodule at an outside institution. The histologic sections and very limited paraffin section immunohistochemical stains performed at our institution revealed a lymph node with architectural effacement by an abnormal infiltrate of lymphoid cells.
Flow cytometric immunophenotypic studies performed at the outside institution demonstrated the infiltrate of abnormal lymphoid cells to be lymphoblasts, expressing: CD45, CD3, CD79a, CD4, CD8, CD5 (dim), CD7, CD2, and TdT.