[Clinicopathological features of follicular lymphoma in children]

Objective: To investigate the clinicopathologic features of follicular lymphoma (FL) in children. Methods: One female and one male patients with FL diagnosed in the First College of Clinical Medical Science, China Three Gorges University and Beijing Friendship Hospital of the Capital University of Medical Science in February 2016 and June 2015 were studied by HE immunohistochemistry, EBER in situ hybridization, IgH and IgK gene rearrangement analysis and IRF4 fusion gene detection. Results: The two patients' age were 6.3 and 12 years, respectively. The lesions involved head and neck lymph nodes with duration of more than 2 months. Histopathologically, the lesions consisted of nodular proliferation of lymphoid follicles with diffuse distribution of large cells. Starry sky phenomenon was seen in one of the two cases. Immunohistochemistry showed that one case was positive for bcl-2 and MUM1, but negative for bcl-6 and CD10. Ki-67 index was>50% and oligoclonal IgK rearrangement was observed. The second case showed positivity for bcl-6, and CD10 but negative for bcl-2. Ki-67 index was>50% and clonal IgH FR1-JH and IgH FR2-JH rearrangements were detected. Both cases showed no evidence of IRF4 gene fusion. Conclusions: Childhood FL is a rare B-cell lymphoma with characteristic features and high-grade histomorphology. However, its immunophenotype and molecular genetic characteristics are divergent.