Angioimmunoblastic T cell lymphoma (AITL) is one of the most common T-cell lymphomas, second only to peripheral T-cell lymphoma not otherwise specified (PTCL-NOS). Initially AITL was considered a non-malignant lymphadenopathy with immune hyperactivation, nowadays being classified as a PTCL.

Lymphoma represents the most common form of hematological malignancy in the developed world, accounting for 3.6% of all cancers and 55.6% of all blood cancers in Europe, with non-Hodgkin lymphomas (NHL) representing 90% of cases.

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease with variable outcomes. The majority of patients benefit from chemo-immunotherapy; however, 30 to 40% relapse after first-line treatment, and 10% are refractory to first-line treatment. This variability in outcome has led to the identification of prognostic factors to stratify patients based on their risk of relapse. The five-factor international prognostic index (IPI) was formulated for such risk stratification more than 20 years ago, based on clinical information obtained from patients with aggressive lymphomas treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP)-like chemotherapy. The addition of rituximab to CHOP chemotherapy led to improved outcomes, diminishing the discriminatory capacity of IPI amongst risk groups. Efforts to enhance the prognostic model by adding or defining new factors have only led to minor improvements without the ability to identify patients at risk of an inferior outcome.

Adult T-cell leukemia/lymphoma (ATL) was first described in the Southwest islands of Japan in 1977 [1]. Then, the HTLV-1 (human T-lymphotropic virustype 1) was isolated in the United States in 1981 in two patients, one with mycosis fungoïdes and the other with Sezary syndrome [2,3], which have been consequently renamed.

Mantle cell lymphoma (MCL) is a rare subtype of non- Hodgkin Lymphoma (NHL) characterized by cyclin D1 translocations. Outcomes are heterogenous, but the disease is generally incurable. High-risk patients been shown to have a median overall survival (OS) of only 37 months and 20% five-year OS. In some patients, the disease is more indolent; such cases are associated with leukemic phase of the disease, SOX11-negativity, and mutated IGHV. Additionally, even across SOX11 positive cases outcomes vary, with worse overall survival in MCL with cytoplasmic staining as compared to nuclear staining. For patients with indolent clinical behavior, observation is frequently employed, and large case series suggest the possibility of prolonged periods before treatment becomes necessary, as long as 128 months, and favorable outcomes even once treatment has been initiated.