Clinico-pathological Findings and Diagnostic Challenges in Angioimmunoblastic T Cell Lymphoma.

UNLABELLED: Angioimmunoblastic T-cell lymphoma (AITL) is a rare mature T-cell neoplasm with diverse clinical presentations and frequent bone marrow (BM) involvement. Its diagnosis can often be challenging due to atypical features, both in the clinical presentation as well as laboratory findings. We retrospectively analyzed 30 AITL cases that underwent bone marrow examination at our centre between 2017 and 2024. Clinical, laboratory, and flow cytometry (FCM) findings were compared between cases with and without BM involvement. BM involvement was observed in 63.3% of the cases, and correlated with lower hemoglobin level and positivity for direct Coombs test. Unusual presentations included isolated hypereosinophilia, pure red cell aplasia, plasmacytosis, paraneoplastic cranial nerve palsy, and initial misdiagnosis as Hodgkin lymphoma. FCM showed consistent CD4+/CD8- phenotype, frequent CD3 and CD7 downregulation, and expression of two markers related to T follicular helper cell (TFH) phenotype (CD10 and PD-1). AITL may present with clinical and laboratory findings mimicking other neoplastic as well as non-neoplastic diseases. Recognizing unusual presentations is critical for AITL diagnosis. Flow cytometric immunophenotyping aids in early and accurate detection. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at https://doi.org/10.1007/s12288-025-02255-w.