Background: The typical route of metastatic spread of testicular seminoma is through lymphatic pathways, whereas hematogenous dissemination is less frequent. The thyroid is a rare site of metastases from any cancer, but any patient with a previous oncologic disease should inquire about a thyroid nodule.
Case report: We present a case of a 37-years-old man with a testicular seminoma with a peculiar metastatic spread behavior, with previously unreported histological findings. The initial clinical appearance was of a stage I testicular tumor with normal tumor markers. Nevertheless, the tumor appeared to have spread directly to the thyroid gland and subsequently to latero-cervical nodes, about 3 years after the first diagnosis. Perhaps the patient could have been treated with chemotherapy alone, as he developed a second cancer 6 years after the diagnosis, and that event could have been related to delivered therapies, mainly radiotherapy.
Conclusion: This type of seminoma spread has previously been described only once, and it is not a typical route for metastasis by seminoma. In view of this unusual finding, we reinforce the need for accurate diagnostic planning of any thyroid nodule occurring in a patient with a previous cancer history. Accurate staging is crucial in planning the treatment and follow-up of seminoma. Currently, greater attention is due to management of the disease at diagnosis, as emerging data support a risk of a second cancer among patients treated with radiotherapy and chemotherapy for a testicular cancer.