Marrow Notes

Malignant testicular neoplasms Type Features Germ cell (95%)Seminoma• Retain features of spermatogenesis • β-hCG, AFP usually negative Nonseminoma• ≥1 partially differentiated cells: yolk sac, embryonal carcinoma, teratoma, and/or choriocarcinoma • β-hCG, AFP usually positive Stromal (5%)Leydig• Often produces excessive estrogen (gynecomastia) or testosterone (acne) • Can cause precocious puberty Sertoli• Rare • Occasionally associated with excessive estrogen secretion (eg, gynecomastia) AFP = alpha-fetoprotein. This patient with a testicular mass, gynecomastia, and elevated estrogen levels likely has a Leydig cell tumor, the most common type of testicular sex cord stromal tumor. These tumors arise from supporting cells of the testis such as Leydig, Sertoli, and granulosa cells; they account for approximately 5% of testicular tumors (germ cell tumors account for ~95%), arise in a wide range of ages, and have no clearly defined risk factors. Leydig cells are the primary source of testicular testosterone but are also capable of generating estrogen. Therefore, Leydig cell tumors often present with endocrine manifestations due to excessive estrogen (eg, gynecomastia, loss of libido, erectile dysfunction) or testosterone (eg, acne, hirsutism). Examination frequently reveals a testicular mass, which is typically confirmed by bilateral scrotal ultrasound. In contrast to many germ cell tumors, Leydig cells do not generally produce serum tumor markers such as β-hCG or alpha-fetoprotein (AFP). However, the generation of estrogen or testosterone often leads to FSH and LH suppression. (Choices A, D, and E) Choriocarcinoma, teratoma, and yolk sac tumors are nonseminomatous germ cell tumors. They typically present with a painless, firm testicular mass. However, they often produce β-hCG (particularly choriocarcinoma) or AFP (particularly yolk sac tumors) in addition; estrogen production is rare, so feminization is uncommon. (Choice C) Seminoma is a germ cell tumor that does not usually produce β-hCG, AFP, or estrogen. Therefore, feminization would be atypical. Most seminomas present with a painless, unilateral testicular mass or swelling. TAKE HOME MESSAGE Leydig cell testicular tumors often cause feminization (eg, gynecomastia) due to the production of estrogen by tumor cells. This frequently causes secondary inhibition of FSH and LH. Serum tumor markers (eg, β-hCG, AFP) are not usually elevated.