Massively Enlarged Kidneys Due to Leukemic Infiltration in a Child

Flow cytometry-Recognizing unusual populations in leukemia and lymphoma diagnosis

Flow cytometry is an invaluable technology in the examination of blood, bone marrow, tissue and body fluids for the presence or absence of hematological disease. It is used in both diagnostic and follow-up testing, with an increasingly important role in the detection of very small residual disease populations (Minimal Residual Disease, MRD) However, flow cytometry immunophenotyping of leukemia and lymphoma is highly dependent on interpretation of results and with the increased complexity of 8-10 color instruments routinely used in clinical laboratories, knowledge of disease-defining populations is increasingly important as is recognizing normal and reactive patterns. This manuscript presents case studies with flow cytometric patterns encountered in routine screening of samples sent for leukemia and lymphoma immunophenotyping, focusing mainly on B-cell disorders which may be missed or incorrectly interpreted by the laboratory (including a hematopathologist) performing the test. Case studies are used to illustrate our laboratory's standardized approach to the interpretation of flow cytometric data. In addition to a standardized approach, these cases emphasize the importance of interpretative skills of technologist and hematopathologists in recognizing abnormal patterns in detecting hematological malignancies.

Acute interstitial nephritis in T-cell leukemia in a pediatric patient

Acute lymphoid leukemia is the most frequently occurring malignancy in childhood, but acute tubulointerstitial nephritis with associated acute renal failure as the leading manifestation of leukemia is extremely rare. Only a few pediatric cases have been described in the literature. We present a surprising case in which physical examination and initial investigation were not typical for leukemia. Ultrasound showed only modest kidney enlargement while laboratory results indicated acute renal failure. Renal biopsy indicated tubulointerstitial nephritis, and subsequent steroid treatment led to sudden clinical improvement. One month later, however, the patient returned with typical clinical features of leukemia. Re-evaluation of the original kidney biopsy block indicated T-cell acute lymphoid leukemia. The present case highlights the importance of renal biopsy.