Lessons From the Friday Unknowns
The patient is a 41-year-old female with common variable immunodeficiency (CVID) (agammaglobulinemia).
Histologic sections show core biopsies with a polymorphous infiltrate composed of predominantly small, mature-appearing lymphocytes with scattered admixed larger lymphoid cells (somewhat resembling Hodgkin cells) and histiocytes.
Mild focal sclerosis can be appreciated in the background. There is no increase in plasma cells or eosinophils in the background. No increased mitotic activity, apoptosis or necrosis seen.
Immunohistochemical stains show that the larger atypical lymphoid cells express CD20 (strong), PAX5, CD30, CD45, BCL6 (subset), MUM-1; they do not express CD10, CD15 or PD-1. Ki-67 stain highlights the larger lymphoid cells, and the overall proliferation index is ~5%. CD20 stain also highlights many small B-cells and focal nodules. CD3 and BCL2 stains highlight many small T-cells.
CD10 stain highlights stromal elements; no follicles are seen by CD10 or BCL6 stains. CD21 stain highlights scattered residual follicular dendritic cell meshworks. CD45 stain diffusely highlights the lymphocytes as well as the scattered larger cells. PD-1 stain highlights a subset of cells; no rosette formation is present. Epstein-Barr virus-encoded small RNA (EBER) in situ hybridization stain highlights numerous positive cells (~40% of all cells).
These findings are supportive of the diagnosis of EBV-positive polymorphous PTLD.
Link to digital slides: bit.ly/321kceP | Slides labeled case 3