BCL2-Negative Follicular Lymphoma
Lessons From the Friday Unknowns
Histologic sections show lymph node extensively replaced by lymphoma. The neoplasm also extends into perinodal adipose tissue and has an entirely follicular pattern. Most of the follicles are composed of a variable mixture of centrocytes and centroblasts supporting grade 2 overall.
The cells within the follicles are positive for CD10, CD20, PAX-5 and BCL-6, and are negative for CD3, CD21, CD23 and BCL-2. Many follicular dendritic cells within the follicles are positive for CD21 and CD23. The antibody specific for Ki-67 shows a range of positive cells within follicles, ranging from 10% in some follicles up to 40–50% in other follicles.