[Key points in the diagnosis of T-cell lymphoma in the 5th edition of the WHO Classification (2022)].

The diagnosis of T-cell lymphoma poses challenges compared to B-cell lymphoma, as it is difficult to conceptualize a normal cellular counterpart, and morphological identification of origin is nearly impossible. With limited specific markers, clinical information (e.g., lesion distribution, clinical course, and symptoms) is extremely important for diagnosis. The 5th edition of the WHO Classification clarified the classification for T/NK cell lymphomas. Key changes include the addition of the "tumor-like lesion with T-cell predominance" category. EBV-related T/NK lymphomas were also reorganized, and the classification and differential diagnosis of TFH phenotype lymphomas were refined. As many aspects of T-cell lymphomas remain unclear, pathologists and hematologists must work in close collaboration to integrate pathological findings with crucial clinical data to ensure accurate diagnosis.