Expansion
Germ cell tumours predominate, divided into seminoma and non-seminoma
Expansion
Germ cell tumours (about 95 per cent)
- Seminoma: peak age 30s, radiosensitive, excellent prognosis. AFP is never raised; beta-hCG may be mildly raised
- Non-seminomatous: embryonal carcinoma, yolk sac tumour (commonest in young children, raised AFP), choriocarcinoma (markedly raised beta-hCG, early haematogenous spread), teratoma, and mixed tumours
Non-germ cell
- Leydig cell: may secrete androgens or oestrogens, causing precocious puberty or gynaecomastia
- Sertoli cell
- Lymphoma: the commonest testicular tumour over 60
Risk factors: cryptorchidism (risk persists in the contralateral descended testis too, and orchidopexy reduces but does not abolish it), previous testicular tumour, family history, infertility, Klinefelter syndrome.
Lymphatic spread is to para-aortic nodes, not inguinal, reflecting the embryological origin. This is why staging requires abdominal imaging and why a scrotal approach to biopsy is avoided.
The marker rule is worth stating precisely: pure seminoma never produces AFP, so a raised AFP indicates a non-seminomatous component and the tumour is treated as such.