Retrospective study of the radiological findings of the mediastinum after end-of-treatment for a mediastinal lymphomatous mass in pediatric oncology

Pauline Tibout, Judith Rondeau-Legault, Guillaume St-Laurent, Natasha Ferguson, David Simonyan, Valérie Larouche


INTRO Reactive thymic hyperplasia following chemotherapy in children treated for mediastinal lymphoma can be misdiagnosed as tumor relapse. This phenomenon may cause unnecessary imaging or diagnostic procedures. 

OBJECTIVES The main objective of this study was to measure the incidence of reactive thymic hyperplasia following treatment for mediastinal lymphoma in children. The secondary objectives were to describe the radiologic findings which may help differentiate thymic hyperplasia and tumor relapse and to analyse if the finding of a mediastinal mass changed the clinical management of the patient. 

METHODSThe medical and radiologic records of 72 pediatric patients who had completed two years of follow-up after treatment for mediastinal lymphoma were reviewed in this retrospective study. The radiologic imaging reports were analysed and the patients were classified depending on whether they developed a mediastinal mass during follow-up or not. If a mass developed, its characteristics were described in order to differentiate between tumor relapse and thymic hyperplasia. 

RESULTS Thirty-nine (54%) patients had developed a mediastinal mass during follow-up. Thirty-five of them had no relapse, and their mass was classified as reactive thymic hyperplasia. Three patients had a mediastinal tumor relapse. In 12/35 (34%) patients having a benign mediastinal mass at follow-up, the clinical management was modified based on the radiological findings. 

CONCLUSIONReactive thymic hyperplasia is a common phenomenon, as it developed in half of our cohort of patients. Some radiological findings, including a triangular shape, well-defined margins and mild homogenous enhancement, oriented towards a rebound thymic hyperplasia. 


Lymphoma; Rebound Thymic Hyperplasia; Recurrence

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