Abstract
BACKGROUND: The involvement of the testis by metastatic medullary thyroid carcinoma has never been described before. We describe the first case of metastatic medullary thyroid carcinoma affecting testis and inguinal lymph nodes. CASE PRESENTATION: A 73-year-old Caucasian man was referred to undergo urologic surgery due to a painless nodule in the right testis and an homolateral inguinal lymphoadenomegaly. The patient had a history of medullary thyroid carcinoma with relapsing disease to the spine and lung nodules. Serum calcitonin and CEA levels were 175 pg/ml and 22 ng/ml, respectively. With suspected testicular cancer, the patient underwent radical right orchiectomy with the excision biopsy of the right inguinal lymph node. Histopathology and immunohistochemistry revealed that both the lesions were due to metastases from medullary thyroid carcinoma. CONCLUSION: Metastases to the testis and inguinal lymph nodes may be due to various solid and hematological tumors. This case, despite its rarity, suggests that testis and inguinal lymph nodes should be considered as potential secondary sites of medullary thyroid carcinoma as well.