PurposeWe aimed to investigate the relationship between histopathological and immunohistochemical features of male breast cancer (MBC) and comprehensive fluorine-18-fluorodeoxyglucose (F-18-FDG) PET/computed tomography (CT) parameters.MethodsFifteen male patients with newly diagnosed breast cancer who underwent F-18-FDG PET/CT were included in the study. Maximum and average standardized uptake value (SUVmax and SUVavg), metabolic total volume, and total lesion glycolysis (TLG) were compared with the histopathological and immunohistochemical findings of patients. In addition, metabolic tumor-node-metastases (TNM) staging was performed following the determination of metastatic axillary lymph nodes and tumor size by F-18-FDG PET/CT and verified by histopathological evaluation.ResultsThere were no significant differences between all groups classified on the basis of histopathological and immunohistochemical parameters for SUVmax, SUVavg, TLG, and metabolic total volume. The only difference was found in patients with distant metastases and stage IV. SUVmax, SUVavg, and TLG were higher in patients with distant metastases compared with patients without distant metastases (P: 0.005, 0.011, and 0.042, respectively). Strong correlations were found between metabolic TNM staging and histopathological TNM staging (for T stage; r: 0.590, P: 0.021, N stage; r: 0.694, P: 0.002, TNM stage; r: 0.835, P: 0.002). In addition, no differences were found with any metabolic F-18-FDG PET/CT parameters in survival.ConclusionAlthough no correlation was found between metabolic parameters and groups categorized on the basis of histopathological or immunohistochemical features, F-18-FDG PET/CT is a reliable imaging modality to determine tumor size, axillary lymph node involvement, and metabolic TNM staging of MBC. In addition, none of those metabolic F-18-FDG PET/CT parameters predicted survival in MBC.