A Developing Anterior Mediastinal Mass in a Breast Cancer Patient: Thymic Hyperplasia

Abstract

Introduction: True thymic hyperplasia following chemotherapy has been described mostly in children. There are a few cases of thymus hyperplasia that have been reported in breast cancer patients. Diagnosis of this unusual entity is very crucial to pretend unnecessary surgery or interventional diagnostic procedures. Case Presentation: We report a case of thymus hyperplasia in a patient who was operated and treated with adjuvant chemotherapy for stage 2 breast cancer two years ago. In the follow-up CT scans, an anterior mediastinal mass was noted. Radiologic evaluation and follow-up revealed thymus enlargement. Discussion: Thymic hyperplasia following chemotherapy has been described in both children and adults, but occurs mostly in children and adolescents treated for lymphoma and several other types of tumors. Few cases are reported in literature describing thymus hyperplasia following chemotherapy in a breast cancer patient. The imaging findings of thymic hyperplasia on CT, MRI and PET CT are discussed. Conclusion: Radiologists must be aware of this unusual finding in breast cancer patients treated with chemotherapy to guide the clinicians appropriately in order to avoid unnecessary surgical intervention, additional invasive diagnostic procedures, or chemotherapy.