Microscopic Description and Lab Work-Up

Histology:  Diffuse infiltration, vesicular nuclei with one to several nucleoli. Frequent mitotic figures.  "starry sky" pattern by numerous macrophages with ingested apoptotic debris.  Prominent nucleoli, basophilic cytoplasm with many vacuoles onTouch preps (diff-quik)

IHC stains: Positive for CD20, CD10, bcl-6, but  negative for CD5, bcl-1, and bcl-2. Ki67 (proliferation rate approaching 100%).

Immunophenotyping:  Predominant abnormal B cell population (> 90% of the lymphocytes gated); positive for CD19, CD20, CD22, CD10, FMC7, and surface lambda light chain restriction. Negative for CD5, and CD23. Predominantly intermediate cell (based on forward-scatter signal)

(Burkitt's Lymphoma)