Clinical analysis of thymic regrowth following chemotherapy in children and adolescents with malignant lymphoma.
OBJECTIVE
Thymic regrowth following chemotherapy has typical clinical and imaging manifestations that can be used to diagnose it prior to pathological diagnosis. We investigated methods for diagnosing thymic regrowth following chemotherapy with non-invasive methods.


METHODS
Our study included 26 children and adolescents with thymic regrowth following chemotherapy for malignant lymphoma. Computed tomography scans were routinely performed for follow-up observations. After the emergence of new mediastinal masses, patients either underwent Fluorine-18 ﬂuorodeoxyglucose-positron emission tomography scans to identify the characteristics of the mass, or were closely followed up.


RESULTS
Thymic regrowth occurred 1-12 months after the last chemotherapy (mean, 4 months). Computed tomography mostly revealed diffusely enlarged thymic parenchymatous tissues that maintained normal thymic morphology. Computed tomography values were 36.72 ± 9.48 Hu and increased by 5.56 ± 2.62 Hu in contrast enhancement. The mean volume of the mass was 19.2 cm(3). Twenty patients underwent positron emission tomography; among them, five (25%) showed no intake of Fluorine-18 ﬂuorodeoxyglucose in the anterior mediastinal mass, and 15 (75%) showed radioactivity distribution in the mass with a mean standardized uptake value of 2.7; the shape was regular and radioactivity distribution was uniform. The mean follow-up duration was 40 months and all patients achieved disease-free survival.


CONCLUSIONS
In the absence of pathological diagnosis, thymic regrowth following chemotherapy can be diagnosed by clinical features combined with characteristic manifestations in computed tomography and positron emission tomography scans.
Zhen
Zijun
Z
Department of Pediatric Oncology, Cancer Center, Sun Yat-Sen University, Guangzhou, China.
Sun
Xiaofei
X
Xia
Yi
Y
Ling
Jiayu
J
Cai
Yue
Y
Wang
Juan
J
Guan
Zhongzhen
Z
D000293:Adolescent; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D018572:Disease-Free Survival; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008223:Lymphoma / Q000188:drug therapy* / Q000473:pathology*; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals; D013950:Thymus Gland / Q000000981:diagnostic imaging / Q000473:pathology*; D013997:Time Factors; D014057:Tomography, X-Ray Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18