T-Cell Lymphoma: Causes, Symptoms, Treatment and Prognosis — Overview, Diagnosis & Treatment Options | MyMedicPlus

T-cell lymphomas (TCL) are a heterogeneous group of non-Hodgkin lymphomas arising from mature T-lymphocytes or natural killer (NK) cells at various stages of differentiation, collectively comprising approximately 10-15% of all non-Hodgkin lymphomas. The 5th edition WHO Classification of Haematolymphoid Tumours (2022) recognises over 30 distinct entities. Major subtypes include peripheral T-cell lymphoma NOS (PTCL-NOS, approximately 25% of TCL), angioimmunoblastic T-cell lymphoma (AITL, approximately 20%), anaplastic large cell lymphoma ALK-positive and ALK-negative (ALCL), adult T-cell leukaemia/lymphoma (ATLL), and extranodal NK/T-cell lymphoma nasal type (ENKTL). Cutaneous T-cell lymphomas (mycosis fungoides and Sézary syndrome) are addressed as a separate disease group. Compared to B-cell lymphomas, TCL are more aggressive overall, have a higher frequency of adverse prognostic features including bone marrow involvement and B symptoms, and have fewer approved targeted therapies. Annual incidence in the US is approximately 5,000-6,000 cases, with higher rates in Asia and Japan for specific subtypes including ATLL and ENKTL.

The aetiology of T-cell lymphomas involves viral oncogenesis, immunosuppression, and acquired somatic mutations. HTLV-1 (human T-cell leukaemia virus type 1) retroviral infection is the causally established agent for adult T-cell leukaemia/lymphoma (ATLL), endemic in southwestern Japan, the Caribbean basin, West Africa, and the Middle East; only 2-4% of HTLV-1 carriers develop ATLL over a lifetime, with a latency period of decades. Epstein-Barr virus (EBV) is pathogenetically central to ENKTL (detected by EBER in situ hybridisation in virtually all cases) and plays a role in AITL via EBV-reactivation in the lymphoma microenvironment. Immunodeficiency states — HIV/AIDS, post-organ transplant immunosuppression, and primary immunodeficiency syndromes — increase T-cell lymphoma risk across multiple subtypes. Key recurrent molecular alterations include: TET2 somatic mutations (early founder mutations in T-follicular helper cell-derived AITL); RHOA G17V hotspot mutation (approximately 50-70% of AITL), defining AITL's molecular identity; IDH2 R172 mutations in AITL; CD28 mutations and CTLA4-CD28 fusions; and the t(2;5)(p23;q35) translocation producing the NPM-ALK fusion kinase in ALK-positive ALCL. Breast implant-associated ALCL (BIA-ALCL) is a distinct indolent entity linked specifically to textured surface breast implants.

The clinical presentation of T-cell lymphoma varies substantially by subtype and anatomical distribution of disease. Systemic subtypes (PTCL-NOS, AITL, ALK-positive ALCL) typically present with peripheral or generalised lymphadenopathy and prominent constitutional B symptoms: fever (temperature exceeding 38°C on more than 50% of days for 14 consecutive days), drenching night sweats requiring change of bedclothes, and unintentional weight loss greater than 10% of body weight over 6 months. AITL additionally causes polyclonal hypergammaglobulinaemia, autoimmune haemolytic anaemia, positive Coombs test, skin rash (urticarial or maculopapular), pleural effusions, and ascites — reflecting its complex immune dysregulation. ALCL frequently presents as bulky abdominal or mediastinal disease with systemic spread and bone marrow infiltration; ALK-positive ALCL tends to occur in younger patients (median age 30-35 years) while ALK-negative ALCL occurs in older patients. ENKTL (nasal type): nasal obstruction, epistaxis, midline facial destruction (historically termed 'lethal midline granuloma'), and palatal perforation from angioinvasive tumour. ATLL: leukaemic phase with circulating 'flower cells', hypercalcaemia (from PTHrP secretion), skin lesions, and opportunistic infections from HTLV-1-induced immunosuppression. Hepatosplenomegaly is a common feature of aggressive subtypes.

Tissue diagnosis requires excisional lymph node biopsy rather than core needle biopsy wherever possible, given the complexity of TCL subtyping and the need for adequate material for IHC, molecular, and cytogenetic studies. The diagnostic panel includes a broad T-cell IHC panel: CD2, CD3, CD4, CD5, CD7, CD8, CD30, CD56, TIA-1, granzyme B, ALK, and PD-1 (TFH marker for AITL). T-cell receptor (TCR) gene rearrangement studies (TCRβ and TCRγ by PCR or NGS) confirm clonality. ALK testing by IHC and FISH is mandatory for ALCL subclassification. HTLV-1 serology and ATLL-specific morphological assessment for patients at risk or with compatible presentation. EBV detection by in situ hybridisation (EBER) is essential for ENKTL diagnosis. Comprehensive next-generation sequencing (NGS) panels are increasingly used to detect RHOA G17V, TET2, IDH2, CD28, and CTLA4 mutations in AITL and related subtypes, informing subtype-specific targetability. PET/CT for staging, bone marrow biopsy (bilateral trephines for nodal TCL), and molecular staging including clonal TCR detection in peripheral blood for Sézary syndrome. The PIT (Prognostic Index for T-cell lymphoma) score guides prognosis in nodal TCL.

The treatment of T-cell lymphoma is subtype-specific and remains an area of active investigation with many patients enrolled in clinical trials. ALK-positive ALCL: the FDA-approved first-line regimen is brentuximab vedotin plus CHP (cyclophosphamide, doxorubicin, prednisone — BV-CHP), which replaced CHOP based on superior 3-year EFS demonstrated in the ECHELON-2 trial; for Stage I-IIA limited disease, 2-4 cycles of CHOP or BV-CHP followed by involved-field radiotherapy is an alternative. PTCL-NOS, AITL, and ALK-negative ALCL: standard first-line is CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) or CHOEP (adding etoposide); CD30-positive PTCL-NOS and AITL may benefit from BV-CHP. Consolidation with autologous SCT in first complete remission is recommended for all eligible patients with PTCL-NOS, AITL, and ALK-negative ALCL given high relapse rates with chemotherapy alone. ENKTL (early stage, upper aerodigestive): concurrent IMRT (50 Gy) plus L-asparaginase-based chemotherapy (SMILE or AspaMetDex); advanced-stage or relapsed ENKTL: pembrolizumab shows approximately 30-40% ORR. ATLL: aggressive subtypes (acute, lymphomatous) have dismal prognosis; intensive combination chemotherapy followed by allogeneic SCT for eligible patients; mogamulizumab (anti-CCR4, expressed on ATLL cells) for relapsed/refractory. Salvage regimens for relapsed PTCL include pralatrexate, romidepsin, belinostat (HDAC inhibitors), gemcitabine-oxaliplatin (GemOx), and clinical trials with PI3K inhibitors.

Prevention of T-cell lymphoma is largely focused on reducing exposure to known causative agents and managing immune risk factors. HTLV-1 prevention — the established cause of ATLL — requires strategies to reduce viral transmission: HTLV-1-endemic populations should be counselled on transmission routes (sexual contact, breastfeeding, blood transfusion, sharing needles). Blood donation services in endemic countries screen for HTLV-1 antibodies. Breastfeeding by HTLV-1-positive mothers is discouraged or limited to less than 6 months in some guidelines to reduce mother-to-child transmission. There is currently no HTLV-1 vaccine available. EBV, the driver of ENKTL, is ubiquitous, and there is no approved EBV vaccination for lymphoma prevention; however, mRNA-based EBV vaccines are in clinical development. For breast implant-associated ALCL (BIA-ALCL), the FDA and major surgical societies recommend against the use of textured-surface breast implants in new placements, and monitoring of patients with existing textured implants for new peri-implant seromas or masses. Patients receiving long-term immunosuppressive therapy following organ transplantation should be monitored for post-transplant lymphoproliferative disorder, which may include T-cell variants. Reduction in immunosuppressive intensity and addition of antiviral therapy are interventions targeting EBV-driven PTLD.

Seek prompt medical evaluation if you experience the following symptoms, which may indicate T-cell lymphoma or another serious haematological malignancy. Rapidly enlarging painless lymph nodes in the neck, axilla, or groin lasting more than 2-4 weeks without an obvious infectious cause require evaluation. Constitutional B symptoms — soaking night sweats requiring change of clothing, unexplained fever exceeding 38°C for more than 2 weeks, or unintentional weight loss of more than 10% of body weight over 6 months — are red flags that warrant urgent blood tests and specialist review. Progressive skin rash — particularly if widespread, itchy, or associated with lymphadenopathy — in an adult should be evaluated by a dermatologist and haematologist to exclude cutaneous T-cell lymphoma. Individuals from HTLV-1-endemic regions (Japan, Caribbean, Central Africa) who develop any haematological abnormality, particularly hypercalcaemia, leukaemic blood picture, or skin lesions, should be tested for HTLV-1 antibodies and ATLL. Persistent nasal obstruction, epistaxis, or midline facial destructive lesions — particularly in individuals of East Asian descent — require urgent ENT evaluation and tissue biopsy to exclude ENKTL. Sézary syndrome (erythroderma, generalised lymphadenopathy, circulating Sézary cells in blood) requires urgent haematological and dermatological evaluation.

ALK-positive ALCL: best prognosis among T-cell lymphomas, with 5-year OS approximately 70-80% with BV-CHP. ALK-negative ALCL: approximately 50% 5-year OS. PTCL-NOS: 5-year OS approximately 30-40%. AITL: approximately 30-40%. ENKTL disseminated: approximately 20-30%. ATLL acute/lymphomatous subtypes: median OS less than 12 months with conventional therapy. Clinical trial participation is strongly encouraged given the limited long-term efficacy of existing regimens for most nodal PTCL subtypes. The prognosis for T-Cell Lymphoma: Causes, Symptoms, Treatment and Prognosis varies depending on severity at diagnosis, the patient's overall health, and how promptly treatment is initiated. With early diagnosis and appropriate management, many patients achieve good outcomes and maintain quality of life. Regular follow-up with healthcare providers is essential to monitor progress, adjust treatment as needed, and detect any complications early. Adherence to prescribed treatments and lifestyle modifications significantly improves long-term prognosis.