To investigate the clinicopathological features, insulin resistance (IR) status, and the outcomes of populations with diffuse large B-cell lymphoma (DLBCL) of the breast.This study was carried out at Department of Haematology, the Fourth Hospital of Hebei Medical University, Shijiazhuang, China, that included 32 patients treated form January 2009 to June 2020. The primary endpoints of the study were their survival time.There were 32 patients in the study. A total of 18 (56.2%) patients had IR. In terms of treatment, 31.2% were treated with surgery, most (93.8%) received chemotherapy, and 25% received radiotherapy and intrathecal therapy. Univariate analysis indicated the patients with stages III-IV, B symptoms, tumour recurrence, PAX5 positivity, and c-MYC positivity showed a shorter survival time (p<0.05). The overall survival and progression-free survival (PFS) rates in IR group were shorter than those without IR, but there was no statistical difference (p>0.05). Multivariate analysis indicated that tumour recurrence shortened the 5-year PFS of the patients (p=0.037).Primary DLBCL of the breast was very rare; more than half of the cases had IR, but IR did not affect their survival.Copyright: © Saudi Medical Journal.