Testicular cancer is the most common neoplasm in young males. The early diagnosis and the appropriate treatment make it a curable malignancy in over 90% of the patients, but 6% of the patients with testicular cancer develop a second, mostly treatment-related, malignancy in another primary site many years after the first diagnosis. The simultaneous appearance of a testicular tumor with another primary neoplasm is rarely described in the literature. Here is presented an interesting case of a coexisting non-seminomatous germ cell testicular tumor with a papillary thyroid carcinoma, which was detected early during post-treatment restaging of the testicular tumor. The synchronous presence of these two neoplasms might indicate a probable common pathogenetic background. As treatment-related oncogenesis is highly improbable in this case and the common environmental factors are not known yet, the interest is focused on genetic predisposition. Recent discoveries in molecular genetics show that the two neoplasms share common genetic alterations in the RAS and BRAF genes, which affect the significant signaling pathways. Interestingly, BRAF-V600E was positive in both primary malignancies in our individual.
Keywords: testicular cancer; papillary thyroid carcinoma; synchronous diagnosis.