Abstract:
To study the diagnosis, grading, differential diagnosis, and translocation status of follicular lymphoma ( FL ). Methods: Ninety-eight cases of FL were retrieved and the hematoxylin and eosin-stained slides were reviewed; the representative blocks were selected to construct the tissue microarray. Antigens such as BCL-2, CD10, and Ki-67 were detected by the immunohistochemistry. The bcl-2-MBR and bcl-6-MBR translocation status in FL were tested by dual color FISH. Results: The clinicopathologic findings were as follows: 98 FL patients including 51 males and 47 females ( M:F ratio = 1.09:1 ) with an age range of 25 to 83 years ( median, 59 years ). Up to 54 cases were classified into the low-grade group, 26 cases were grade 3a, and 18 cases were grade 3b. Morphologically, FL presented with typical features, which would play an important role in diagnosis and differential diagnosis through the application of antibodies such as BCL-2, CD10, and Ki-67. In our cohort, the positivity of these three markers was 62.2%, 87.8%, and 50.0%, respectively. FISH: The incidence of bcl-2-MBR in FL was 58.5%, with 91.7% in grade 1, 63.0% in grade 2, 52.0% in grade 3a, and 16.7% in grade 3b, respectively. The translocation frequency was decreased along with the increase of grading. The translocation status had correlation with Ki-67 expression. The incidence of bcl-6-MBR in FL was 16.3%, with 0 in grade 1-2, 35.7% in grade 3, 41.7% in grade 3a, and 27.8% in grade 3b, respectively. All bcl-6-MBR translocations occurred in high grade FL. Conclusion: 1) FL predominantly affected adults, with a median age in the 5th decade. It had a predominantly follicular pattern and typical neoplastic cells. 2) Applying antibodies such as BCL-2, CD10, and Ki-67 could help to make the final diagnosis, combining CD5, CD23, CyclinD1, and CD43 could differentiate FL from reactive hyperplasia and other small B cell NHL. 3) The translocation frequency of bcl-2-MBR was decreased along with the increase of FL grading. The bcl-2-MBR had a correlation with FL grading and Ki-67 expression. 4) The bcl-6-MBR translocation had relationship with FL grading; all translocations occurred in high grade FL.