Clinicopathological diagnosis of Lennert lymphoma: a case report and review of the literature

Abstract

Abstract Background Lennert lymphoma (LL) is a variant of peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS), also known as a lymphoepithelioid variant of PTCL. Because of the rarity and lack of clear-cut diagnostic criteria, LL is susceptible tomisdiagnosis. Although previously diagnosed with LL might be reclassified and evaluated with the advent of of molecular and/or genetic findings, cytomorphology and immunohistochemistry are still the key to give rise to correct diagnosis. Case presentation We report a case of a patient who was diagnosed as LL based on cytomorphology and immunohistochemistry. Routine stain (Hematoxlin and Eosin-H&E) revealed tumor cells were mainly small to medium-sized CD4(+) T cells, the CD8 +/TIA-1 + cytotoxic cells were less minority, no expressions of follicle helper T cell markers (CD10, BCL6, PD1, CXCL13, ICOS) or CD21(+) hyperplastic FDC network, or proliferation of high edndothelial venules were noted; however, numerous epithelioid histiocytes are noted in the background and scattered EBV(+) cells were also present. The patient was achieved complete remission after six courses of chemotherapy with cyclophosphamide, epirubicin, vincristine, etoposide, and prednisone regimen. She was followed for 5 years without recurrence or progression. Conclusions Classic LL is not difficult to diagnose by cytomorphology and immunohistochemistry, and the mutation profiles can be helpful to distinguish LL from other lymphomas.

Keywords

• Lennert lymphoma
• PTCL-NOS
• RS-like cells
• Epithelioid histiocytes
• Case report