Agostinelli C, Akarca AU, Ramsay A, et al. - Thirteen nodal pediatric-type follicular lymphomas (PTFLs) were examined using immunohistochemistry, fluorescence in situ hybridization (FISH), and PCR and were contrasted with a further 20 reactive lymph nodes exhibiting FH in order to review the histopathological, phenotypic, and molecular features of PTFL and to evaluate the diagnostic significance of novel immunohistochemical markers in differentiating PTFL from follicular hyperplasia (FH). Morphologically, PTFL cases showed a follicular growth pattern with irregular lymphoid follicles in which the germinal centers were comprised of numerous blastoid cells exhibiting a starry-sky appearance. In 6/13 cases, preserved CD10 and BCL6 staining, CD20 positivity, a K light chain predominance, and partial BCL2 expression were reflected by immunohistochemistry. In most of the cases, the germinal center (GC)–associated markers stathmin and LLT-1 were positive. FOXP-1 was consistently positive in PTFL vs reactive GCs in FH, where only a few separated positive cells were seen. In the investigated cases, no evidence of BCL2, BCL6, or MYC rearrangements was exhibited by FISH. In 100% of the tested PTFL cases, clonal immunoglobulin gene rearrangements were identified through PCR. Therefore, this study authenticates the unique morphological and immunophenotypic characteristics of PTFL and implies that in the differential diagnosis between PTFL and FH, FOXP-1 could represent a novel beneficial diagnostic marker.