Germ cell neoplasia in situ
Germ cell neoplasia in situ represents the precursor lesion for many types of testicular germ cell tumors.
The term GCNIS was introduced with the 2016 edition of the WHO classification of urological tumours. GCNIS more accurate describes the lesion as it arises between the basement membrane and Sertoli cells. The common, unspecified variant of the entity was once considered to be a carcinoma in situ, although the term "carcinoma in situ" is now largely historical as it is not an accurate description of the process.
Classification
The World Health Organization classification of testicular tumours subdivides ITGCN into a more common, unspecified type, and other specific subtypes. The most common specific subtypes are intratubular embryonal carcinoma and intratubular seminoma.Cancer risk
GCNIS is seen in the following settings:- Almost all invasive germ cell tumours of the testis in adults
- Fifty percent of patients with GCNIS developed invasive germ cell tumours within five years of initial diagnosis.
- Five percent of contralateral testes in men with a history of prior testicular germ cell tumour.
- Less than five percent of cryptorchid testes.
- Less than one percent of patients with infertility.
Germ cell tumors that do not arise from ITGCNU
Not all germ cell tumors arise from intratubular germ cell neoplasia. The following testicular GCTs do not arise from ITGCN:- Spermatocytic tumor
- Pediatric Yolk sac tumors. This is currently an area of controversy as some authors dispute the absence of ITGCN in these cases.
- Teratoma