Reactive Thymic Hyperplasia On CT Following Chemotherapy In Adult Patients With Lymphoma

Objective:Reactive thymic hyperplasia(RTH)is not only occurred in children but also in older patients receiving regular chemotherapy for lymphoma.This study was aimed to report the specific CT findings of thymic in those patients.Methods:Thirty-five patients with malignant lymphoma presenting with RTH and 43 patients without RTH after treatment were included in the present study.The size and density of the thymus were scored by using a thymic index with a scale of 6.The clinical and CT manifestations of both groups were reviewed retrospectively and analyzed by some traditional statistical methods,such as One-way analysis of variance,T-test,and the regression analysis.Results:Fourteen patients(14/35,40%)in RTH group presented thymic atrophy during chemotherapy and showed thymic hyperplasia after withdrawal of chemotherapy.The remaining 21 patients(21/35 60%)have not experienced thymic atrophy before RTH arising.RTH occurred in 5 of 21 patients during chemotherapy,and the rest 16 patients showed RTH a median of 6 months(range 1-12 months)after the termination of chemotherapy.There were no statistically significant differences in age,sex,types,and stage of lymphoma(p=0.096,0.682,0.929,0.323)between patients with RTH and without RTH by univariate analysis.The thymic index was a potential predictor for RTH(P=0.002)in the two groups before therapy.Logistic regression of thymic index showed that patients with a thymic index higher than 0 were more likely to develop RTH after chemotherapy(thymic index=1,P=0.03,OR=4.96,95%CI=1.71-14.38,thymic index≥ 2,P=0.02,OR=13.95,95%CI=2.57-75.59).In addition,the prognosis of the two groups was also statistically different,p=0.037.The survival curve of patients with reactive thymic hyperplasia was higher than that of patients without hyperplasia.Conclusion:The time for RTH emergence in adult patients may be different according to a series of CT follow-up.The thymic index was significantly different before treatment between patients with RTH and without RTH after chemotherapy.Patients with a higher thymic index before treatment were more likely to develop RTH after chemotherapy.Adult lymphoma patients with thymic reactive hyperplasia have a better prognosis.