Abstract:Objective To investigate the clinical value of serum follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels in differentiating benign masses from malignant breast masses in patients with Klinefelter syndrome(KS). Methods Based on the general survey of KS in Qianjiang area,68 patients confirmed with KS treated from January 2015 to December 2017 were retrospectively studied,in whom the patients with breast cancer underwent breast surgery were designed as breast cancer group(n=23),and the patients( excluding breast cancer) were designed as control group(n=45).The levels of FSH,LH,testosterone (T) and prolactin (PRL) were compared between two groups,and their diagnostic efficacy at different truncation values were analyzed by receiver operating characteristic (ROC) curve. Results The levels of FSH,LH and T in breast cancer group were significantly higher than those in control group (P=0.000,0.000,0.008),but there was no significant difference in PRL level between two groups (P=0.757).ROC curve showed that the area under curve(AUC) of FSH,LH and T were 0.944,0.746 and 0.738,respectively.The diagnostic efficiency of FSH for breast cancer was significantly higher than those of LH (P=0.002) and T(P=0.002).Youden′s index indicated that the best cut-off points of FSH,LH and T were 47.722 mIU/ml,22.731 mIU/ml and 1.632 ng/ml,respectively for diagnosing breast cancer,and the accuracy,sensitivity,positive predictive value and negative predictive value of FSH diagnosing breast cancer with KS were significantly higher than those of LH (all P<0.05) at these best cut-off points. Conclusion FSH has high accuracy and sensitivity in differential diagnosis of benign and malignant breast masses in patients with KS and has important clinical significance.