Figure 1: CT Scan in Follicular Lymphoma Grade 3a
CT scan shows a enlarged node measuring nearly 2 cm on size. This was biopsied.
Figure 2: Touch Preparation in Follicular Lymphoma Grade 3a
Variable numbers of small and large cleaved cells are noted in this touch preparation.
Figure 3: H&E in Follicular Lymphoma Grade 3a
Lower and intermediate-power view (three images) show nodular architecture replacing the entire node with monotonous neoplastic follicular structures.
The high power image within the neoplastic follicular structures shows increased numbers of centroblasts admixed with scattered centrocytes allowing designation as grade 3a. Likewise the absence of sheets of centroblasts allows exclusion of grade 3b disease.
Also, note follicular dendritic cells (black arrows), centrocytes (white arrows), and centroblasts (blue arrows). Follicular dendritic cells frequently have doublet nuclei with clear chromatin and small nucleoli while centroblasts have convoluted nuclear contours and multiple membrane-bound nucleoli with clumped but dispersed chromatin. Centrocytes are smaller cells with elongated twisted nuclei and clumped chromatin.
Figure 4: CD20 & CD10 in Follicular Lymphoma Grade 3a
Neoplastic follicles are positive for CD20 but negative for CD10 (in this case). Although most follicular lymphoma express CD10, this case is negative for CD10 in the neoplastic B-cells within the follicles. CD10 however highlights scattered lymphoid cells consistent with follicular helper T-cells (TFH) which are known to express CD10. Normally TFH cells reside at the periphery of secondary germinal centers. TFH cells also express CD4 and PD1 and are the cell of origin of angioimmunoblastic T-cell lymphoma in which the T-cells coexpress CD3 and CD10 frequently.
Figure 5: LMO2 & HGAL in Follicular Lymphoma Grade 3a
The neoplastic follicular B-cells are positive for LMO2 (top two images) with nuclear staining in a significant proportion of cells while HGAL is uniformly positive in these follicules supporting germinal center derivation despite negative CD10.
Figure 6: BCL2 & Ki67 in Follicular Lymphoma Grade 3a
The neoplastic follicles are positive for BCL2 with moderately high proliferation on Ki-67 consistent with grade 3a disease. About 50% of high grade FL may shows loss of BCL2 which is otherwise present in nearly 85-90% of grade 1-2 cases.
