Angioimmunoblastic T-cell lymphoma (AITL) is the second most common subtype of peripheral T-cell lymphomas, accounting for 1-2% of all NHLs and 15-20% of peripheral T-cell lymphomas. Originates from follicular helper T cells (TFH). Typically presents in adults aged 60-70 with generalized lymphadenopathy, hepatosplenomegaly, skin rash, hypergammaglobulinemia, autoimmune hemolytic anemia, and polyclonal B-cell proliferation. Strong EBV association — EBV-positive B-cell expansion accompanies. Histologically characterized by polymorphic infiltrate, prominent arborizing HEV (high endothelial venule) proliferation, and expanded follicular dendritic cell networks. On imaging, generalized lymphadenopathy, hepatosplenomegaly, and concurrent pleural/peritoneal effusions are seen. Prognosis is poor — 5-year survival 30-35%.
Age Range
50-85
Peak Age
65
Gender
Equal
Prevalence
Uncommon
AITL is a malignant lymphoproliferative disease originating from follicular helper T cells (TFH). TFH cells normally direct germinal center B-cell responses; their malignant transformation leads to abnormal cytokine production and immune dysregulation. Characteristically carries RHOA G17V, TET2, DNMT3A, and IDH2 mutations. Tumoral TFH cells secrete abundant VEGF and other angiogenic factors triggering intense arborizing HEV proliferation — this prominent vascular proliferation histologically forms the basis of increased enhancement on imaging. Simultaneously supports polyclonal expansion of EBV-positive B cells — disruption of immune surveillance leads to EBV reactivation and potential B-cell lymphoma transformation. Hypergammaglobulinemia results from polyclonal B-cell activation. Autoimmune hemolytic anemia is related to production of warm antibodies. The homogeneous enhancement of generalized lymphadenopathy on imaging reflects similar levels of lymphomatous infiltration and HEV proliferation across all nodes. Effusions are related to increased vascular permeability and hypoalbuminemia.
In an elderly adult, the combination of generalized symmetric lymphadenopathy, hepatosplenomegaly, pleural/peritoneal effusions, and laboratory hypergammaglobulinemia + autoimmune cytopenia is highly characteristic of AITL. This clinico-radiological constellation provides a strong clue in differentiating from other NHL subtypes.
On B-mode ultrasonography, enlarged, homogeneously hypoechoic lymph nodes are seen at multiple stations (cervical, axillary, inguinal). Hilum is generally lost. Nodes may be oval or round. Hepatosplenomegaly accompanies. Ascites or pleural effusion may be detected.
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On US, enlarged, homogeneously hypoechoic lymph nodes with loss of hilum at multiple stations and hepatosplenomegaly are noted; systemic lymphoproliferative disease (AITL) should be considered.
On contrast-enhanced CT, symmetrically enlarged, homogeneously enhancing lymph nodes are seen at all lymph node stations (cervical, mediastinal, axillary, retroperitoneal, iliac, inguinal). Enhancement is moderate to prominent, reflecting the rich vascularity of HEV proliferation. Necrosis is rare. Hepatosplenomegaly accompanies. Pleural and peritoneal effusions are common (30-50%). Skin thickening may be observed.
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Contrast-enhanced CT demonstrates symmetrically enlarged, homogeneously enhancing lymph nodes at all stations, hepatosplenomegaly, and bilateral pleural effusions; findings are consistent with systemic lymphoproliferative disease (AITL).
On DWI, enlarged lymph nodes demonstrate significant diffusion restriction — bright signal at high b-values and low ADC values (0.6-1.0 × 10⁻³ mm²/s). Similar levels of restriction across all involved nodes. This finding reflects dense cellular infiltration (polymorphic lymphomatous infiltrate).
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On DWI, significant diffusion restriction is noted in enlarged lymph nodes at all stations (ADC: ___×10⁻³ mm²/s), consistent with dense lymphomatous infiltration.
On FDG PET-CT, intense FDG uptake is seen at all lymph node stations (SUVmax generally 8-20+). Increased diffuse uptake may also be seen in spleen and liver. Cutaneous lesions may be FDG-avid. Bone marrow involvement may appear as diffuse increased axial skeleton uptake. AITL is among the most intensely FDG-avid peripheral T-cell lymphomas.
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FDG PET-CT demonstrates intense FDG uptake (SUVmax: ___) at all lymph node stations, increased uptake in hepatosplenomegaly, and bilateral pleural effusions; findings are consistent with AITL.
On color Doppler, increased vascularity is seen in enlarged lymph nodes — mixed or peripheral vascularity pattern predominates. This finding results from intense HEV proliferation and neoangiogenesis in AITL. Low resistance index on spectral Doppler reflects tumoral vascularization.
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Doppler ultrasonography demonstrates increased mixed/peripheral vascularity in enlarged lymph nodes consistent with neoangiogenesis; AITL should be considered in the differential.
On T2-weighted images, generalized enlarged lymph nodes demonstrate homogeneous hyperintense signal. Hepatosplenomegaly and effusions accompany. Splenic T2 signal homogeneity may be disrupted (lymphomatous infiltration foci).
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On MRI T2, generalized enlarged lymph nodes demonstrate homogeneous hyperintense signal with accompanying hepatosplenomegaly and effusions; findings are consistent with AITL.
Criteria
TFH phenotype (PD-1+, CXCL13+, BCL6+, ICOS+) polymorphic infiltrate, prominent arborizing HEV, expanded FDC networks. RHOA G17V mutation in 50-70%.
Distinct Features
Most common form. Generalized LAP + hepatosplenomegaly + effusions + hypergammaglobulinemia typical constellation. Widespread intense uptake on PET-CT.
Criteria
Clonal expansion of EBV-positive B cells in AITL background — diffuse large B-cell lymphoma or EBV-positive Hodgkin-like proliferation may develop.
Distinct Features
More aggressive course. Some nodes with more intense uptake than others on PET-CT (focal increases). Mixed histology on biopsy — AITL + DLBCL components.
Criteria
T-cell lymphoma with TFH phenotype but not fully meeting classic AITL histological features (arborizing HEV, FDC expansion). Defined as separate entity in WHO 2022 classification.
Distinct Features
Imaging findings similar to AITL but effusions and autoimmune findings may be less frequent. Definitive differentiation is made histopathologically and molecularly.
Distinguishing Feature
In other NHL subtypes (DLBCL, follicular), effusions, hypergammaglobulinemia, and autoimmune cytopenia do not accompany as frequently as in AITL. Focal dominant mass is more common in DLBCL while symmetric generalized LAP predominates in AITL.
Distinguishing Feature
In Hodgkin lymphoma mediastinal involvement predominates; in AITL generalized symmetric distribution and effusions predominate. Hypergammaglobulinemia is not expected in Hodgkin.
Distinguishing Feature
In sarcoidosis bilateral hilar LAP predominates with pulmonary involvement; AITL has generalized distribution including peripheral stations. Hypergammaglobulinemia may be present in sarcoidosis but autoimmune cytopenia is rare and effusions not expected.
Distinguishing Feature
In IgG4-related disease specific organ involvements (autoimmune pancreatitis, retroperitoneal fibrosis, salivary gland swelling) accompany; these organ involvements are not expected in AITL. Serum IgG4 elevated in IgG4, polyclonal hypergammaglobulinemia in AITL.
Urgency
urgentManagement
medicalBiopsy
NeededFollow-up
3-monthAITL is an aggressive T-cell lymphoma requiring prompt treatment initiation. Diagnosis is made by excisional lymph node biopsy — TFH immunophenotyping (PD-1, CXCL13, ICOS, BCL6) and molecular tests (RHOA, TET2, DNMT3A, IDH2) support diagnosis. First-line treatment is CHOP or CHOEP chemotherapy. Autoimmune complications (hemolytic anemia, thrombocytopenia) must be managed concurrently. In young patients, high-dose chemotherapy + autologous stem cell transplant consolidation may be considered. EBV viral load should be monitored — risk of B-cell lymphoma transformation exists. Interim and end-of-treatment response assessment with PET-CT. 5-year survival is 30-35%, prognosis slightly better than other peripheral T-cell lymphomas.
AITL has an aggressive clinical course with 5-year survival of approximately 30-35%. First-line chemotherapy with CHOP or CHOEP is administered. Consolidation autologous stem cell transplantation is considered in younger patients. Novel agents such as romidepsin, belinostat, and brentuximab vedotin are used in relapsed cases. EBV-associated complications (hemophagocytic syndrome) may require urgent intervention.