Gynaecomastia caused by a primary mediastinal seminoma

The case of a young man aged 26 is reported. He presented with a short history of painful gynaecomastia, and no other associated symptoms. Radiological investigations showed a mass in the anterior mediastinum. Endocrine investigations showed high circulating oestradiol and high hCG-beta levels. There was no evidence of primary testicular tumour or metastases. Surgical removal of the mediastinal mass led to normalization of oestradiol and hCG-beta levels and regression of gynaecomastia. Histology showed the tumour to be a primary mediastinal seminoma staining positively for hCG-beta. Further treatment consisted of chemotherapy with etoposide and cis-platinum. The patient has remained well with no evidence of disease recurrence. The tumour markers remain normal.