13) Embryonal carcinoma
is positive for CD30, negative for AFP.
18-20) Among the malignant tumors we observed a case of bilateral Dysgerminoma, case of mixed germ cell tumor, case of immature teratoma and a case of Embryonal carcinoma
represents a malignant stem cell tumor with a totipotent differentiation capacity, as demonstrated by Kleinsmith and Pierce (17) as early as 1964 in an experimental murine model that provided the first demonstration of the stem cell origin of cancer.
The differential diagnosis of DLBCL includes germ cell tumors such as classical seminoma, spermatic seminoma and embryonal carcinoma
and non--neoplastic entities like granulomatous and viral orchitis, which need to be ruled out at times using markers.
Germ cell tumours represent a diverse group of neoplasms, including classic seminoma, spermatocytic seminoma, embryonal carcinoma
, YST, choriocarcinoma, teratoma and mixed tumours containing variable amounts of the aforementioned tumour types.
The other mimicker is the tubular variant of seminoma, in which the tumor architecture resembles gland-forming embryonal carcinoma
yet retains the cytologic features of seminoma (Figure 1, B).
21-22) The histologic classification of GCTs at this site is identical to that used in the gonads: seminomatous (pure), nonseminomatous (yolk sac tumor, embryonal carcinoma
, choriocarcinoma, and mixed GCTs), and teratomas.
30) CD30 stains most embryonal carcinomas
and can be used as part of a panel of markers to distinguish metastatic embryonal carcinoma
from somatic carcinoma.
These included 3 metastatic melanomas, 3 EAs, 4 epithelioid hemangiomas of soft tissue, 3 epithelioid mesotheliomas, and 10 metastatic carcinomas with epithelioid morphology (3 RCCs, 2 poorly differentiated carcinomas of unknown primary, and 1 each of gastric signet ring carcinoma, embryonal carcinoma
, squamous carcinoma, lung adenocarcinoma, and colonic adenocarcinoma).
Cells with vesicular nucleus resembling embryonal carcinoma
, bizarre giant cells, areas of necrosis, and frequent mitosis, including abnormal forms and blood vessel invasion, are also seen.
139) In short, there are numerous advantages to the change: It acknowledges that GCNIS is a precursor to both seminomas and NSGCTs without the confusing unclassified" term in the name, it allows distinction from other more differentiated forms of intratubular germ cell neoplasia (intratubular seminoma and intratubular embryonal carcinoma
, discussed further below in the Histologic Features of GCNIS section), the in situ" component more accurately refers to the specific area where this type of GCT arises (the spermatogonial niche), and lastly, it is more consistent with the nomenclature of other precursor lesions in human malignancies.
Both embryonal carcinoma
and dysgerminoma stain for OCT-4,  but only embryonal carcinoma
stains for CD-30.