A rare case of metachronous pituitary germinoma and testicular seminoma: The role of tumor markers in diagnosis and the influence of glucocorticoids on disease progression

The presence of both an extragonadal germ cell tumor and gonadal germ cell tumor is a rare occurrence with few cases reported in the literature. We herein report a case of a young man presenting with hypophysitis due to a pituitary germinoma. After a course of high dose glucocorticoid (GC) therapy and the surgical removal of the germinoma, a testicular seminoma was discovered, an apparently second distinct primary germ cell tumor. Hypophysitis was initially attributed to lymphocytic hypophysitis due to the largely unrevealing secondary work up that included beta-human chorionic gonadotropin (b-hCG) and alpha fetoprotein (AFP), which highlights the pitfalls of relying on the tumor marker of b-hCG in both germinomas and seminomas and the important role of biopsy for definitive diagnosis of hypophysitis etiology. Furthermore, the presentation of the seminoma following a course of high dose GC indicates that immunosuppressive therapies may promote the growth of these germ cell tumors.