Eble JN, Sauter G., Epstein JI, Sesterhenn IA - iarc
Eble JN, Sauter G., Epstein JI, Sesterhenn IA - iarc
Eble JN, Sauter G., Epstein JI, Sesterhenn IA - iarc
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A<br />
B<br />
Fig. 4.09 Spermatocytic seminoma. A Example of G-banding on a metaphase spread. B Comparative genomic hybridization of DNA isolated from the same tumour.<br />
Note the almost complete absence of structural anomalies, while numerical changes are present. Gain of chromosome 9 is the only consistent anomaly identified.<br />
Precursor lesions<br />
Intratubular germ cell neoplasia,<br />
unclassified type (IGCNU)<br />
Definition<br />
Germ cells with abundant vacuolated<br />
cytoplasm, large, irregular nuclei and<br />
prominent nucleoli located within the<br />
seminiferous tubules.<br />
ICD-O code 9064/2<br />
Synonyms<br />
Intratubular malignant germ cell, carcinoma<br />
in situ, intratubular preinvasive<br />
tumour, gonocytoma in situ, testicular<br />
intraepithelial neoplasia, intratubular<br />
atypical germ cells and intratubular<br />
malignant germ cells.<br />
Epidemiology<br />
Adults<br />
In adults with history of cryptorchidism<br />
intratubular germ cell neoplasia, unclassified<br />
are seen in 2-4% {345,787,887,<br />
1010,1124,2040,2131,2222} in contrast<br />
to 0.5% in young children {501}. In infertility<br />
studies, the prevalence is about 1%<br />
{233,345,1900,2346, 2430,2943}) ranging<br />
from 0-5%. Patients with intersex syndrome,<br />
and a Y chromosome have<br />
intratubular germ cell neoplasia of the<br />
unclassified type (IGCNU) in 6-25% of<br />
cases {118,387,1831,2140, 2826}. Testes<br />
harbouring a germ cell tumour contain<br />
IGCNU in a mean of 82.4% of cases,<br />
ranging from 63 {889} -99% {346}. Since<br />
the risk of tumour development in the<br />
contralateral testis is increased about 25-<br />
50 fold {615,1985, 2774}, some centres<br />
in Europe have initiated biopsies of the<br />
contralateral testis, with detection rates of<br />
IGCNU of 4.9-5.7% {613,2749}. IGCNU is<br />
detected in 42% of patients who presented<br />
with retroperitoneal germ cell tumours<br />
{262,555,1100} but is rarely found in<br />
patients with mediastinal tumours {997}.<br />
Several autopsy studies have shown that<br />
the incidence of IGCNU is the same as<br />
the incidence of germ cell tumours in the<br />
general population {616,891}.<br />
Children<br />
In contrast to their adult counterpart, the<br />
true incidence of prepubertal IGCNU is<br />
difficult to assess. IGCNU has only rarely<br />
been described in association with testicular<br />
maldescent, intersex states and in<br />
a very few case reports of infantile yolk<br />
sac tumour and teratoma {1134,1381,<br />
2018,2167,2482,2483}.<br />
IGCNU is seen in association with<br />
cryptorchidism is 2–8% of patients {1381}.<br />
Four of 4 patients with gonadal dysgenesis<br />
in one series had intratubular germ cell<br />
neoplasia of the unclassified type (IGCNU)<br />
{1833} as did 3 of 12 patients with androgen<br />
insensitivity (testicular feminization)<br />
syndrome {1831}. In review of the literature<br />
Ramani et al. found IGCNU in 2 of 87<br />
cases of different intersex states {2140}.<br />
A<br />
B<br />
Fig. 4.10 Precursor lesions of germ cell tumours. A Intratubular germ cell neoplasia (IGCNU) adjacent to normal seminiferous tubules. B Positive PLAP staining in<br />
the intratubular germ cell neoplasia (IGCNU) adjacent to normal seminiferous tubules.<br />
228 Tumours of the testis and paratesticular tissue