A rare association between malignant mediastinal seminoma and other malignant neoplasms.

Primary malignant mediastinal seminomas (PMMS) are rare tumors accounting for 1-6% of all mediastinal tumors. PMMS mostly affect young men, arising from primordial germ cells that abnormally migrate from the ectoderm of the yolk sac to the gonadal region. They are clinically and biologically distinct from primary testicular tumors and seem to have a worse prognosis. Due to the rarity of the disease, the choice of treatment is a matter of debate. Literature data do not show any association between this kind of tumor and malignant Schwannoma or thyroid carcinoma. In this report we describe the case of a patient affected by PMMS and 12 yr later by a malignant brachial plexus Schwannoma and papillary thyroid carcinoma (PTC). Since both mediastinal seminoma and Schwannoma were treated with surgery followed by local radiotherapy, we were not able to ascertain if either PTC or Schwannoma had been induced by radiotherapy or represented a casual neoplastic association.