CD5 & SOX11-Positive B-Cell Lymphoma with Aggressive Features

From the Friday Unknowns

The patient is a 77-year-old man with a recent diagnosis of double hit high-grade B-cell lymphoma (MYC/BCL2 rearrangements). He now presents with FDG avid mass lesion in the left hemiscrotum (3.9 cm, SUV 8.6).

Histologic sections show testicular parenchyma extensively involved by lymphoma.

he lymphoma has a diffuse growth pattern and is composed of sheets of monotonous appearing lymphoma cells that are intermediate in size with irregular nuclear contours, vesicular chromatin, frequent single prominent nucleoli and scant to small amounts of eosinophilic cytoplasm. Mitotic activity is brisk and apoptotic bodies are abundant. No frank tumor necrosis is identified.

Immunohistochemical studies show that the neoplastic cells positive for CD20, CD5 (dim), SOX11, BCL2, C-MYC (30–40%), MUM1; and negative for CD10, BCL6, cyclin D1, TDT and CD34. CD3 highlights T-cells in the background. CD21 shows absence of FDC meshworks. Ki-67 shows a proliferation index of 70- 80%.