Contributed by Alicia F. Liang, MD, Lydia Contis, MD, and Fiona Craig, MD
The patient is a 19-year-old female who presented to the emergency department (ED) with a two week history of general malaise, shaking chills, rash, fevers, night sweats and right upper quadrant pain. She had initially been seen two days prior in the ED, and preliminary evaluation demonstrated tender lymphadenopathy, an erythematous maculopapular rash of the malar region of the face, upper and lower extremities, and an elevated white blood cell count of 33,600 plt/L, with 5% "atypical cells" present. Her hemoglobin and hematocrit were within normal limits (14 g/dL and 42.2%), with an MCV of 84.9. At the time she was deemed well enough to follow up as outpatient with dermatology the following morning; by the time of this appointment she had developed shaking chills. This, in conjunction with the findings of the peripheral blood smear, prompted a second evaluation in the ED, with consultation by hematology
Peripheral blood smear (Wright-Giemsa) demonstrates numerous atypical, small-to-moderately sized lymphoid cells, with irregular, occasionally bilobate nuclear contours. Some cells appear larger, with rounded nuclear contours and basophilic cytoplasm.
Flow cytometry studies were performed on the peripheral blood sample, and demonstrated the following results: a population of mature T-cells which were mostly CD3+, CD2+, CD5 mostly negative, CD7 mostly +, CD8 negative, CD4+, HLA-DR+, CD1a negative, TdT negative, CD7 mostly +, partial CD13+, CD34 negative, CD117+. A portion of the CD4+ T-cells also coexpressed CD26; these cells were CD7 negative. The majority of the total population was also CD25+.
A bone marrow biopsy and aspirate were then obtained.
The bone marrow biopsy appears hypocellular for age (40%), with small atypical lymphoid cells identified throughout the marrow. The infiltrate is difficult to appreciate on the biopsy section, and is highlighted by immunohistochemical staining. These appear similar to the cells seen in the peripheral blood. Few of these cells were noted in the marrow aspirate. To further characterize these cells, immunohistochemical studies were performed on the biopsy.
There are scattered CD30+ cells throughout the bone marrow biopsy. There is a predominance of CD3+ T cells (see image), with only scattered CD20+ cells (not shown). These T cells are also positive for expression of CD2 and CD4 (not shown), and decreased positivity for CD5 and CD8 (not shown).
Fluorescence in-situ hybridization studies were also performed on the marrow, and demonstrated ALK gene rearrangement [t(2;5)(p23;35) in 79 of 209 cells analyzed (37.8%)].