Pediatric-type follicular lymphoma

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