Editing Germ cell tumor (section)

==Classification==
[[File:Relative incidences of testicular tumors.png|thumb|Germ cell tumors constitute a vast majority of the incidences of [[testicular tumor]]s.<ref>{{cite journal| author=Gill MS, Shah SH, Soomro IN, Kayani N, Hasan SH| title=Morphological pattern of testicular tumors. | journal=J Pak Med Assoc | year= 2000 | volume= 50 | issue= 4 | pages= 110–3 | pmid=10851829 | doi= | pmc= | url=https://pubmed.ncbi.nlm.nih.gov/10851829  }}</ref>]]
GCTs are classified by their [[histology]],<ref name=pmid15761467>{{cite journal | vauthors = Ulbright TM | title = Germ cell tumors of the gonads: a selective review emphasizing problems in differential diagnosis, newly appreciated, and controversial issues | journal = Modern Pathology | volume = 18 | issue = Suppl 2 | pages = S61–S79 | date = February 2005 | pmid = 15761467 | doi = 10.1038/modpathol.3800310 | doi-access = free }}</ref> regardless of location in the body. However, as more information about the genetics of these tumors become available, they may be classified based on specific gene mutations that characterize specific tumors.<ref>{{cite journal | vauthors = Maoz A, Matsuo K, Ciccone MA, Matsuzaki S, Klar M, Roman LD, Sood AK, Gershenson DM | display-authors = 6 | title = Molecular Pathways and Targeted Therapies for Malignant Ovarian Germ Cell Tumors and Sex Cord-Stromal Tumors: A Contemporary Review | journal = Cancers | volume = 12 | issue = 6 | page = 1398 | date = May 2020 | pmid = 32485873 | pmc = 7353025 | doi = 10.3390/cancers12061398 | doi-access = free }}</ref> They are broadly divided in two classes:<ref>{{EMedicine|med|2246|Germinoma, Central Nervous System}}</ref>
* The germinomatous or seminomatous germ-cell tumors (GGCT, SGCT) include only [[germinoma]] and its synonyms [[dysgerminoma]] and [[seminoma]].
* {{anchor|Nonseminoma}}The nongerminomatous or nonseminomatous germ-cell tumors (NGGCT, NSGCT) include all other germ-cell tumors, pure and mixed.

The two classes reflect an important clinical difference. Compared with germinomatous tumors, nongerminomatous tumors tend to grow faster, have an earlier mean age at time of diagnosis (around 25 years versus 35 years, in the case of [[testicular cancer]]s), and have a lower five-year survival rate. The survival rate for germinomatous tumors is higher in part because these tumors are very sensitive to radiation, and they also respond well to chemotherapy. The prognosis for nongerminomatous tumours has improved dramatically, however, due to the use of platinum-based chemotherapy regimens.<ref>{{cite book | vauthors = Robbins SL, Kumar V, Cotran RS | title = Robbins Basic Pathology | publisher = Saunders | location = Philadelphia | year = 2003 | page = [https://archive.org/details/robbinsbasicpath0000unse/page/664 664] | isbn = 0-7216-9274-5 | edition = 7th | url-access = registration | url = https://archive.org/details/robbinsbasicpath0000unse/page/664 }}</ref>

=== Germinomatous ===

{| class="wikitable"
|-
! Tumor
! [[ICD-O]]
! Peak Age (yr)
! [[Benign]] or [[malignant]]
! Histology
! Tumor marker
|-
| [[Germinoma]] (including dysgerminoma and seminoma)
|
| 40–50
| Malignant
| Sheets of uniform polygonal cells with cleared cytoplasm; lymphocytes in the stroma
| About 10% have elevated [[Human chorionic gonadotropin|hCG]]<!-- are these all mixed tumors? -->
|-
| [[Dysgerminoma]]
| {{ICDO|9060|3}}
|
|
|
|
|-
| [[Seminoma]]
| {{ICDO|9061|3}}
|
|
|
| Placental alkaline phosphate (PLAP)<ref name=pmid2148879>{{cite journal | vauthors = Nielsen OS, Munro AJ, Duncan W, Sturgeon J, Gospodarowicz MK, Jewett MA, Malkin A, Thomas GM | display-authors = 6 | title = Is placental alkaline phosphatase (PLAP) a useful marker for seminoma? | journal = European Journal of Cancer | volume = 26 | issue = 10 | pages = 1049–1054 | year = 1990 | pmid = 2148879 | doi = 10.1016/0277-5379(90)90049-y }}</ref>
|}

=== Nongerminomatous ===

{| class="wikitable"
|-
! Tumor
! [[ICD-O]]
! Peak Age (yr)
! [[Benign]] or [[malignant]]
! Histology
! Tumor marker
|-
| [[Embryonal carcinoma]]
| 9070/3
| 20–30
| Malignant
| Poorly differentiated, pleomorphic cells in cords, sheets, or papillary formation
| secrete hCG, [[alpha-fetoprotein|AFP]]
|-
| [[Endodermal sinus tumor]], also known as yolk sac tumor (EST, YST)
| 9071/3
| 3
| Malignant
| Poorly differentiated endothelium-like, cuboidal, or columnar cells
| 100% secrete AFP
|-
| [[Choriocarcinoma]]
| 9100/3
| 20–30
| Malignant
| Cytotrophoblast and syncytiotrophoblast without villus formation
| 100% secrete hCG
|-
| [[Teratoma]] including mature teratoma, [[dermoid cyst]], immature teratoma, teratoma with malignant transformation
| 9080/0-9080/3
| 0–3, 15–30
| Mature teratoma, dermoid cyst usually benign (but [[Watchful waiting|follow-up]] required); others usually malignant
| Very variable, but "normal" tissues are common
| Pure tumors do not secrete hCG, AFP
|-
| [[Polyembryoma]]
| 9072/3
| 15–25
| ?
| ?
| ?
|-
| [[Gonadoblastoma]]
| 9073/1
| ?
| ?
| ?
| ?
|}

=== Mixed ===

{| class="wikitable"
|-
! Tumor
! [[ICD-O]]
! Peak Age (yr)
! [[Benign]] or [[malignant]]
! Histology
! Tumor marker
|-
| Mixed
|
| 15–30
| Malignant
| Depends on elements present 
| Depends on elements present
|}

Mixed germ cell tumors occur in many forms. Among these, a common form is teratoma with endodermal sinus tumor.

Teratocarcinoma refers to a germ cell tumor that is a mixture of [[teratoma]] with [[embryonal carcinoma]], or with [[choriocarcinoma]], or with both.<ref>{{MeSH name| Teratocarcinoma}}</ref>  This kind of mixed germ cell tumor may be known simply as a teratoma with elements of embryonal carcinoma or choriocarcinoma, or simply by ignoring the teratoma component and referring only to its malignant component:  embryonal carcinoma and/or choriocarcinoma. They can present in the [[anterior mediastinum]].{{cn|date=May 2021}}