Testicular germ cell tumours: overview
- Topic
Most testicular tumours are germ cell tumours of young men; nearly all grow from an in situ lesion and carry extra chromosome 12p.
What it is
Testicular tumours are the commonest solid cancers of men aged roughly 15 to 35. Almost all are germ cell tumours. Those of adults develop from germ cell neoplasia in situ (GCNIS), a lesion that starts in fetal life, and carry isochromosome 12p or other gains of 12p. They are seminomas or nonseminomatous germ cell tumours (embryonal carcinoma, yolk sac tumour, choriocarcinoma, teratoma), often mixed. Prepubertal tumours (teratoma, yolk sac tumour) and the spermatocytic tumour of older men are not derived from GCNIS. Risk factors are cryptorchidism, gonadal dysgenesis, androgen insensitivity, a family history and Klinefelter syndrome (mediastinal tumours).
Structure
- Testis enlarged by a firm mass; biopsy through the scrotum is avoided, the testis is removed through the groin.
- Background tubules show GCNIS in most adult tumours.
- Immunohistochemistry separates types: OCT3/4 in seminoma and embryonal carcinoma, CD30 in embryonal carcinoma, glypican-3 and AFP in yolk sac tumour, hCG in choriocarcinoma.
Clinical notes
- A painless firm testicular mass in a young man is cancer until proven otherwise.
- Testicular cancer mortality in Latin America has not fallen as much as in high-income countries, reflecting access to treatment.
Test yourself
Think of the answer, then tap the question to see it.
What precursor lesion gives rise to most adult testicular germ cell tumours?
Germ cell neoplasia in situ (GCNIS).
Which chromosomal abnormality is typical of adult germ cell tumours?
Isochromosome 12p, or other gains of 12p.
What does an elevated AFP mean in a patient with a seminoma on histology?
That the tumour contains nonseminomatous (yolk sac) elements, because pure seminoma does not make AFP.
Where do testicular tumours first spread by lymphatics?
To the para-aortic retroperitoneal lymph nodes.
Elsewhere in DurgiPedia
- Tumour markers: serum and tissue, and what each one is for
- Pathways of spread and the usual metastatic sites
- Alpha-fetoprotein (AFP)
- Lactate dehydrogenase (LDH) as a lab marker
- Tumour markers: principles of use
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Testicular Cancer (StatPearls (NCBI Bookshelf), 2024); Testicular cancer mortality in Latin America and the Caribbean: trend analysis from 1997 to 2019 (BMC cancer, 2023).
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Representative model, for educational purposes only.