A young female patient showed up with mediastinal bulky disease and lymph node swelling in her left supraclavicular region. Clinical and histological investigations proved nodular-sclerosing Hodgkin's lymphoma. The patient received combined modality treatment according to the protocols of the German Hodgkin's Disease Study Group and achieved complete remission. Six months later the chest X-ray and thoracic CT-scan showed mediastinal tumor masses suggesting relapsed Hodgkin's disease. Surprisingly, the histological investigation showed thymic hyperplasia as well as the absence of any signs of Hodgkin lymphoma. Thymic hyperplasia is well known as a potential differential diagnosis of mediastinal space-occupying lesions and also as a long-term complication in patients cured of Hodgkin's disease. A detailed case report and a complete review of literature are provided.