Search

Background: Pediatric-type follicular lymphoma (PTFL) is a rare distinct type of mature B-cell lymphoma that has characteristic clinical and pathological features. However, it may have morphological overlap with other non-neoplastic condition like reactive follicular hyperplasia (RFH) and neoplastic condition like usual follicular lymphoma (UFL). All these conditions have different treatment considerations and prognoses and therefore they must be differentiated from each other. Aim: Aim of this study is to review the existing literature to understand the clinical, pathological, and molecular features of PTFL with a focus on microscopic and immunophenotypic features to differentiate PTFL from its histological mimicries. Methods: We searched for research papers in PubMed using the key words “pediatric” and “follicular lymphoma” and included the relevant articles for the literature review. In addition, we also reviewed the latest WHO Classification of Tumors of Hematopoietic and Lymphoid Tissues. Conclusions: PTFL is an indolent tumor mainly presenting as a stage I disease in the head and neck region. Under the microscope, it is mainly composed of large, closely packed, and merging follicles which are positive for CD20, CD10 and BCL6 with a high Ki67 proliferation rate but are negative for BCL2. Particularly, PTFL does not show BCL2, BCL6, IRF4 or MYC translocations. Surgical excision is the current treatment of choice.

The relationship of Epstein-Barr virus (EBV) has been well characterized with a wide range of lymphoproliferative lesions and lymphomas of B-cell, T-cell, and NK-cell origin. However, the association of EBV with mantle cell lymphoma (MCL) is exceedingly rare and not well established. We report a case of classic MCL which transformed to pleomorphic MCL after a clinical course of 19 years. Particularly, EBV infection was detected in the transformed high-grade pleomorphic MCL. Molecular and genetic analyses confirmed the clonal relationship between the original and transformed lymphomas. To the best of our knowledge, there has only been one case reported in 2003 which documented an EBV-associated high-grade transformation of MCL. Therefore, our case report further expanded the spectrum of EBV in the pathogenesis of B-cell lymphoma transformation.