Thymic Seminoma with Regressive Changes Obscured by Granulomatous Reaction.

Primary thymic seminoma is an exceedingly rare tumour. There are few case reports about mediastinal thymic seminoma accompanied by secondary changes. We report a case of a 29-year male admitted to our hospital because of chest pain and dyspnea for 8 months. Computed tomography of the thorax revealed hypodense, solid masses showing calcification and cystic degeneration in the anterior mediastinum. Histopathological examination of the resected specimen revealed a diagnosis of thymic seminoma with regressive and reactive changes. The present case was unique in its presentation as a primary seminoma showing combination of cystic degeneration, follicular hyperplasia, fibrosis, calcification and granulomatous reaction in one case. High level of suspicion is necessary to identify seminomas in a thymic lesion accompanied by secondary changes. Excluding the possibility of metastasis from testicular seminoma is very important before making this diagnosis. Key Words: Thymus, Seminoma, Granuloma, Calcification, Cyst.