A 65-year-old man presented in November 2024 with a persistent cough but no other symptoms. Imaging revealed bilateral axillary, mediastinal, and hilar lymphadenopathy. Right axillary excisional lymph node biopsy showed a CD4⁺ T-cell lymphoproliferative disorder with TRBC1 restriction and aberrant CD7 loss. PCR confirmed T-cell receptor gene rearrangement. By immunohistochemistry, cells were CD3+, CD4+, CD279+, ICOS+, BCL6-, CXCL13-, CD10-, CD30-, TCL1A-, and Ki-67 ≈10%. The lymph node architecture was preserved without atypia. Next generation sequencing showed no pathogenic variants. Peripheral blood and bone marrow each contained a small monoclonal CD4⁺ T-cell population (9% and 5%, respectively). Staging PET showed mild FDG-avid nodes (SUV ≤ 5.6) limited to supradiaphragmatic sites. He also had calcified mediastinal lymph nodes, and splenic granulomas. On interval imaging, most nodes decreased in FDG avidity/ size without treatment, with the exception of new mildly enlarged distal external iliac lymph nodes (SUV max 3.2 from 2.3 previously).
Despite reproducible clonal findings, the morphologic and clinical features have followed an indolent course so far. The case raises the question of whether this represents an indolent CD4⁺ T-cell clonal process-analogous to T-cell clones of uncertain significance-versus PTCL-NOS. Secondary drivers, including prior granulomatous infection or autoimmune inflammation were excluded. Given clinical stability, the patient remains on close observation. Expert input is sought on classification, risk of progression, and optimal surveillance for such atypical clonal T-cell proliferations.
