[Angioimmunoblastic T-cell lymphoma: histopathological grading and prognosis]

Objective: To investigate the histological features and prognostic factors of angioimmunoblastic T-cell lymphoma (AITL). Methods: The pathological data of 62 patients with AITL with complete follow-up information were retrospectively collected and analyzed from Changhai Hospital during September 2012 and September 2017. Histological and immunohistochemical (IHC) examination, in situ hybridization (ISH), and single nucleotide polymorphisms (SNP) gene mutation analysis were done. Subgroup evaluation with histology, IHC, ISH, SNP gene mutation, and association with clinical progression were performed. Results: The cohort included 62 cases of AITL, including 46 males and 16 females patients, with a median age of 64 years. Follicular dendritic cells (FDC) area showed significantly expansion (≥30%) in 40 cases; increased plasma cells (≥10%) was seen in 37 cases; B cells were distributed around blood vessels in 37 cases; and increased p53 mutation positive cells (≥40%) were seen in 39 cases; high Ki-67 index (≥40%) was seen in 39 cases; RHOA mutation was seen in 19 cases; TET2 mutation was seen in 9 cases. Overall survival analysis showed these factors were significantly correlated with tumor prognosis (P<0.05). Multivariate analysis showed that CD38 positive cells<10%, Ki-67≥40%, RHOA and TET2 mutations were risk factors associated with overall survival. Conclusions: AITL could be divided into two different prognostic groups, low-grade and high-grade, with statistically significance outcome, based on the FDC area expansion, degree of plasma cell proliferation, B cells distribution pattern combined with gene mutations and clinical progression. Low-grade malignant group progresses slowly, and high-grade malignant group is highly invasive.