Angioimmunoblastic T-cell lymphoma (AITL) is the second most common subtype of mature T-cell lymphoma (MTCL). It is caused by monoclonal proliferation of T-follicular helper (TFH) cells. Although advances have been made in its biological knowledge, its treatment is still an unmet medical need. We would like to present a case of Nodal-TFH; AITL that we followed in our clinic.

A 67-year-old male patient presented with cough. Thorax CT revealed left supraclavicular-mediastinal multiple lymphadenopathy with pleural effusion. Supraclavicular LN excision was reported as NHL; nodal follicular T helper cell lymphoma, angioimmunoblastic type. Immunohistochemical CD3, PD-1 and CXC13 were positive, CD4, CD8 and CD10 were sparse, CD21 and 23 were positive in increased dentritic cells, CD20, CD30, EBER and IDH-1 were negative. PET-CT revealed Stage 4BS (multiple LNs with FDG uptake in head-neck, thorax-mediastinum and abdominopelvic FDG uptake, increased FDG uptake in bone marrow-spleen; B symptom: positive). Subcutaneous (sc) Azacitidine + intravenous CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) was started. The 1st course of azacitidine was administered at 75 mg/m2 for 7 days 1 week before CHOP treatment and the following courses were administered at 75 mg/m2 for 14 days 2 weeks before CHOP treatment. After 4 cycles of Azacitidine+CHOP, PET-CT regressed and 2 more cycles of treatment were administered. During the follow-up, the patient's general condition deteriorated and he went into septic shock.

AITL-containing T-follicular helper; nodal PTCL is characterized by recurrent mutations affecting epigenetic regulators. The association of abnormal DNA methylation with lymphomagenesis provides rationale for the administration of hypomethylating agents. The epigenetic modifier azacitidine, which inhibits DNA methyltransferase, has demonstrated clinical activity alone or in combination in relapsed/refractory PTCL. In a phase-2 clinical trial of 20 patients who experienced oral azacitidine + CHOP as initial treatment for PTCL, CR was 76.5%, 1-year PFS 61.1%, 1-year OS 88.9%. In our case, we added the hypomethylating agent azacitidine to the CHOP protocol and aimed to evaluate the efficacy of this combination in the initial treatment of CD30 negative PTCL.