Outcome of residual mediastinal masses of thoracic lymphomas in children: impact on management and radiological follow-up strategy

Background. Following treatment with chemotherapy and radiotherapy, patients with thoracic lymphomas may demonstrate benign residual mediastinal masses, composed of inflammatory, fibrous or necrotic tissue. Because of the potential risk of viable tumour cells within the mass, histological verification of the nature of these masses may be requested. Objective. To study the outcome of thoracic lymphomas in children in order to optimise the radiological follow-up strategy of residual mediastinal masses (RMM). Materials and methods. A retrospective study of 39 children [24 with Hodgkin's disease (HD), 10 with non-Hodgkin's lymphoma (NHL), and 5 with anaplastic lymphoma (AL)]. The results of chest X-rays (CXR) and thoracic CT performed at the time of re-assessment were compared with the histology of the residual masses (n = 11) or the clinical course (n = 28). Results. At the time of re-evaluation, 16/39 patients had residual mediastinal enlargement (RME) on CXR, and 18/39 patients had RMM on CT. Good concordance was observed between the two imaging modalities (K = 0.69). Two children with a RMM died from extra-mediastinal progression. Two children with NHL had active residual mediastinal lesions but neither had RMM. Sixteen cases of RMM were observed in the remaining 35 children and 9 of these masses were histologically verified as benign. A favourable course was observed in these 35 cases. Conclusions. RMM are frequent and generally benign. They are well shown on CXR and have a non-specific appearance on CT. Except when required by a treatment protocol, they could be submitted to further radiological follow-up before contemplating surgical verification.