Authors: Jui Choudhuri, MD; Yanhua Wang, MD

A 77-year-old male with history of Diabetes mellitus and hypertension presented with weakness and left inguinal lymphadenopathy. HIV testing was negative. White blood cell count was 8.0k/uL(Reference 4.8-10.08k/uL) with predominantly neutrophils, hemoglobin 10.4g/dL (Reference 14-17.4g/dL) and platelet count 214k/uL (Reference 150-400k/uL).

Flow cytometry of the lymph node biopsy (Image 1) shows approximately 75% abnormal B-cells, positive for CD5 and CD19 (Image 1A), CD20(dim) and CD10 negative (Image 2B), positive for CD23 (Image 1C), negative for CD38 (Image 1D), kappa (dim) restricted (Image 1E) and positive for CD200 (Image 1F). 

Lymph node biopsy (Image 2) morphologically shows effacement of the nodal architecture with very occasional pale proliferation centers (Image 2A, hematoxylin and eosin, original magnification X100).  There are also areas of necrosis with granulocytic infiltration and adjacent to these are cells with nuclear inclusions, showing features of margination, multinucleation and molding (Image 2B, original magnification X400; 2C original magnification X1000). The small lymphocytes are positive for CD20 (original magnification X100), CD5 and negative for CD3 (original magnification X100). HSV immunostaining (original magnification X400) highlights the nuclear inclusion. Both flow-cytometry and biopsy findings confirm a diagnosis of SLL with superimposed HSV infection.