Objective To explore the influence factors in hematoma formation after removing benign breast lesions with an ultrasound-guided vacuum-assisted system.Methods A total of 232 females with 312 benign breast masses received excisional biopsy with ultrasoundguided vacuum-assisted system.The pathology of patients,results of hematoma development and outcome,influence factors for hematoma occurrence(nodule size,nodule location,number of nodule,breast shape,menstrual period,efficacy time of bandage,and application of hemostatic agents during the procedure) were recorded.Results Pathologic examination revealed fibroadenomas in 138 lesions,fibroadenosis in 127 lesions,intraductal papillomas in 39 lesions,inflammatory change in 4 lesions,retention cyst of the breast in 3 lesions,and benign phyllodes tumor in 1 lesion.Thirty hematomas were observed in patients(9.6%).Finally,97.0%hematomas were absorbed completely within 6 months follow-up.The incidence rates of hematoma were increased by 24.7%,10.0%,63.2%,13.9%in the nodule diameter larger or equal to 25 mm group,removal of larger or equal to two nodules once time from one patient group,menstrual period group,and larger and loose breast group,respectively(all P<0.05).However,the incidences were decreased by 60.6%in the bandage performed for 12-24 hours or beyond 24 hours group(P<0.05).The multiple logistic regression models revealed that nodule size(x~2=15.227,P<0.001),number of nodule(x~2=7.767,P=0.005),menstrual period(x~2=24.530,P<0.001),and breast shape(x~2=9.559,P=0.002) were independent risk factors associated with hematoma occurrence,but efficacy time of bandage was a protective factor associated with hematoma occurrence.Conclusion The occurrence of hematoma after the minimally invasive operation was associated with nodule size,number of nodule,menstrual period,breast shape,and efficacy time of bandage. Objective To explore the influence of factors in hematoma formation after removing benign breast lesions with an ultrasound-guided vacuum-assisted system. Methods A total of 232 females with 312 benign breast masses received excisional biopsy with ultrasound-guided vacuum-assisted system. The pathology of patients, results of hematoma development and outcome, influence factors for hematoma occurrence (nodule size, nodule location, number of nodule, breast shape, menstrual period, efficacy time of bandage, and application of hemostatic agents during the procedure) were recorded. Results Pathologic examination revealed fibroadenomas in 138 lesions, fibroadenosis in 127 lesions, inflammatory changes in 4 lesions, retention cyst of the breast in 3 lesions, and benign phyllodes tumors in 1 lesion.Thirty hematomas were observed in patients (9.6%). Finally, 97.0% hematomas were distributed completely within 6 months follow-up. The incidence rates of hematoma were increased by 24.7%, 10. 0%, 63.2%, 13.9% in the nodule diameter larger or equal to 25 mm group, removal of larger or equal to two nodules once time from one patient group, menstrual period group, and larger and loose breast group, respectively (all P <0.05) .However, the incidences were decreased by 60.6% in the bandage performed for 12-24 hours or beyond 24 hours group (P <0.05). The multiple logistic regression models revealed that nodule size (x ~ 2 = 15.227, P (P <0.001), number of nodule (x ~ 2 = 7.767, P = 0.005), menstrual period (x ~ 2 = 24.530, factors associated with hematoma occurrence, but efficacy time of bandage was a protective factor associated with hematoma occurrence. Confound The occurrence of hematoma after the minimally invasive operation was associated with nodule size, number of nodule, menstrual period, breast shape, and efficacy time of bandage.