An 18-year-old man presented with a rapidly growing conjunctival tumor without satellite lesions. Incisional biopsy showed infiltration by a lymphoid proliferation with nodular architecture (panel A; hematoxylin, eosin, and saffron [HE&S] stain), partially ulcerating the mucosa. The infiltrate was made of lymphoid follicles with irregular borders, wide germinal centers, and starry-sky pattern (panel B; HE&S stain). The cells were medium-sized and blastoid in appearance, with clear chromatin (panel C; HE&S stain). Rare centroblasts were also identified, as were apoptotic bodies and scattered mitotic figures. Mantle cuffs were either absent or attenuated. The interfollicular areas were dominated by small lymphocytes. Immunohistochemistry revealed that tumor cells were positive for CD20 (panel D); CD10, PAX5, and BCL6 (panel E); and negative for BCL-2 SP66clone (panel F); and MUM1, cyclin D1, cMYC, and TdT (panel G). CD21 showed a network of follicular dendritic cells (panel H). Ki67 labeling index in germinal centers exceeded 90% (panel I). Polymerase chain reaction for immunoglobulin heavy chain gene rearrangements identified a predominant B-cell clone, ruling out follicular hyperplasia. Epstein-Barr virus encoded RNA in situ hybridization was negative. No rearrangement of BCL2, BCL6, IRF4 or MYC (Vysis probe) genes was found by fluorescence in situ hybridization, thus eliminating lymphoma with IRF4 rearrangement or Burkitt lymphoma, and CD10 positivity is not indicative of primary cutaneous follicular lymphoma.

Altogether, our findings were consistent with follicular lymphoma presenting features of pediatric-type follicular lymphoma in an unusual location.