Follicular Lymphoma

Supplemental Studies

B lineage (CD20 or CD79a) positive
Immunoglobulin 90%
- Variably demonstrable in paraffin sections
bcl2 90%
- Grade 1 nearly 100% positive
- Specific vs. reactive follicles
- Not specific vs. other small B cell lymphomas
CD10 85%
- Specific vs. other small B cell lymphomas
CD5 <5%
CD43 7%
CD23 0-25% (lymphoma cells)
- Follicular dendritic cells present in follicles
bcl1 negative

Immunoglobulin gene rearrangements useful in difficult cases
- Both heavy and light chains rearranged in almost all cases
- More than one clonal rearrangement may be detected in some patients
t(14;18) translocation involving bcl2 present in >85% of follicular lymphoma in USA
- 27-67% of Europeans and Asians
- Not specific for follicular lymphoma