Soft Tissue, Follicular Lymphoma, BCL2 stain

Follicular lymphoma (FL) is the most common form of non-Hodgkin lymphoma, originating from mature B cells. Histology exhibits nodal effacement by closely packed follicles, containing centrocytes and centroblasts. Germinal centre markers, CD10 and BCL-6, are generally positive. Most cases of FL are associated with t(14; 18)(q32;q21) translocation, leading to constitutive BCL-2 expression.

Grading of FL is based on the average number of centroblasts per high power field, and the information is contained in the clinical discussion for LMP65823, see link in Related Content. Adding to the previous discussion, however, diffuse areas with high histologic grade (i.e. grade 3) should be designated as diffuse large B-cell lymphoma (DLBCL), as the clinical management reflects such a diagnosis. This specimen was graded 1-2/3.

This slide shows BCL2 stain. H&E stain and immunohistochemistry for CD20, CD10, BCL6, and MIB1 are included in the Related Content section. MIB1 count was about 20%. The case was negative for CD5 and Cyclin D1 (also known as BCL1).