yolk sac tumor emedicine

7/26/2019 Yolk Sac Tumor Emedicine

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The classification of malignant ovarian germ cell tumors is modified from the 2003 World Health Organization

histologic classification of tumors of the ovary (see Table 3). !" #$

Table 3. %lassification of &alignant Ovarian 'erm %ell Tumors(Oen Table in a ne indo)

Primitive germ cell tumors

Dysgerminoma

Yolk sac tumor

Embryonal carcinoma

Polyembryoma

Nongestational choriocarcinoma

Mixed germ cell tumor, specify components

Biphasic or triphasic teratomas

mmature teratoma

Mature teratoma !benign"

Monodermal teratoma and somatic#type tumors associated $ith mature teratoma %hyroid tumor group

&arcinoid group

Neuroectodermal tumor group

&arcinoma group

Melanocytic group

'arcoma group

'ebaceous tumor group
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Pituitary#type tumor group

(etinal anlage tumor group

)ther

*efinition

+ol, sac tumors are those that resembles the yol, sac" allantois" and e-traembryonic mesenchyme. They arealso ,non as endodermal sinus tumors.

idemiology

+ol, sac tumors (+/Ts) can be seen in males and females" involving the testis" ovary" and other sites" such asthe mediastinum. +ol, sac tumors (+/Ts) of the testis are observed in 2 forms or age grous ure +/T in

young children and mi-ed tye in adults.

1ure yol, sac tumor (+/T) is the most common testicular neolasm in reubertal children" accounting for 0of testicular germ cell tumors in this age grou" ith a median age of 4.# years. 5n adults" yol, sac tumor (+/T)resents as a comonent of mi-ed nonseminomatous germ cell tumor" ith an age averaging 2#630 years. +ol,sac tumor (+/T) comonents are resent in !06#0 of nonseminomatous germ cell tumors in the adult testis. 4"2$

5n children" yol, sac tumors (+/Ts) are more common in 7sians than in hite or blac, ersons. 5n adults" thesetumors are more common in hite individuals than in other races.

tiology

The etiology of yol, sac tumors (+/Ts) is essentially un,non. 5t is seculated that hyermethylation ofthe RUNX3gene romoter and overe-ression of '7T76!" a transcrition factor that regulates differentiation

and function of yol, sac endoderm" may lay imortant roles in the athogenesis of yol, sac tumors (+/Ts).3"!$Hoever" these hyotheses have not been validated.

8ocation

+ol, sac tumors (+/Ts) of the testis are located in the testis arenchyma.

%linical 9eatures and 5maging

%hildren ith yol, sac tumors (+/Ts) usually resent ith ainless testicular masses" hich are tyically bul,ylesions. &etastasis is uncommon at resentation" occurring in less than 40 of cases. 5n adults" yol, sactumors (+/Ts) are associated ith other germ cell comonents such as embryonal carcinoma"choriocarcinoma" teratoma" and seminoma as a art of a mi-ed germ cell tumor. :o secific symtoms e-cettesticular mass are resent. 7lmost all the atients ith a yol, sac tumor (+/T)" either in ure form or mi-edform have a significantly elevated serum alha fetorotein (791).

The resence of hair" bone" or cartilage (the elements of a teratoma) can be seen in a testicular mass in adultsby radiograhic e-amination" hich may or may not be associated ith yol, sac tumor (+/T) comonents. Theradiograhic findings are secific for malignant mi-ed germ cell tumors but are not secific for yol, sac tumors(+/Ts).

8i et al investigate comuted tomograhy (%T) findings of yol, sac tumors ith athological correlation. Thestudy concludes that +/T usually aears as a large solid6cystic mass ith intratumoral hemorrhage" casulartear" mar,ed heterogeneous enhancement" and enlarged intratumoral vessels on %T images. 5ntratumoralcalcification and fatty tissue" although rare" may indicate a mi-ed +/T containing teratoma comonent. #$


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'ross 9indings

'rossly" yol, sac tumors (+/Ts) are solid gray6hite ith a gelatinous" my-oid" or mucoid aearance.:ecrosis" cystic changes" and hemorrhage are often seen. 5n adults" the gelatinous aearance of thesetumors is mingled ith the gross findings of the other germ cell tumor comonents; therefore" the overallaearance of a yol, sac tumor (+/T) is heterogeneous.

&icroscoic 9indings+ol, sac tumor (+/T) of the testis is comosed of rimitive tumor cells" hich are relatively small and lessleomorhic relative to those in embryonal carcinoma" another common subtye of malignant germ cell tumorof the testis.

+/T cells may form many histologic atterns resembling embryonal structures. The most common attern seenin the ma


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/chiller6*uvall body. 7 /chiller6*uvall body is astructure resembling the endodermal sinus" characterized by the resence of a central vessel" surrounded by fibrous tissue

and eithelial tumor cells" in a sace lined by flat tumor cells.Hyaline globules ranging from 4 to #0 microns can be seen in yol, sac tumors (+/Ts)" hich are eriodic acid6/chiff stain (17/) ositive and diastase6resistant. Occasionally" the hyaline globules can be ositive for 791.osinohilic bands (e-tracellular basement membrane material) are fre>uent findings in yol, sac tumors(+/Ts). ither hyaline globules or eosinohilic bands are secific for these tumors.

5mmunohistochemistry

+ol, sac tumor (+/T) cells are ositive for 791" hich can be detected on tissue sections as ell as in theserum of the atients ith these tumors.?$ Hoever" 791 is not secific for yol, sac tumors (+/Ts)" as othertumors such as heatocellular carcinomaand heatoblastomacan also be ositive for 719.=$ %yto,eratin isresent in almost all the cases" and vimentin can be ositive in sindle cell atterns. 7ro-imately !060 ofcases of yol, sac tumors (+/Ts) are ositive for lacental al,aline hoshatase (1871)" a mar,er of severaldifferent subtyes of germ cell tumors.

5n the ast fe years" other mar,ers of yol, sac tumors (+/Ts) have been reorted. 7 romising mar,er thathas been identified is glyican 3" hich is a membrane6bound hearan sulfate roteoglycan. 7s a mar,er foryol, sac tumors (+/Ts)" glyican 3 is more sensitive but less secific than 791" as glyican 3 can be detectedin choriocarcinoma(hich ill be discussed in a searate athology article) and a small ercentage ofimmature teratomas" in addition to liver cancers.$

&olecular@'enetics

Chromosomal changes

The loss of the short arm of chromosome 4 (43?) and the long arm of chromosome ? (?>) as ell as gain ofthe long arm of chromosomes 4 and 20 have been reorted in yol, sac tumors (+/Ts). 5n addition"isochromosome 42" hich is characteristic of other malignant testicular germ cell tumors" can be detected.

Expression signature

There is limited information in the literature regarding the gene e-ression signatures of yol, sac tumors(+/Ts). Hoever" a fe aers have demonstrated the molecular signature of these tumors based one-ression from microarrays studies. A$

Tumor /read and /taging

Of children ith yol, sac tumors (+/Ts)" 06A0 of the tumors are stage 5 disease. The resence of a yol, sactumor (+/T) comonent in stage 5 tumors has been associated ith decreased li,elihood of occult metastasis.
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1rognosis and 1redictive 9actors

Without treatment" this tumor is highly aggressive in children and ill lead to death. With a combination ofmodern surgical treatment and ad

yolk sac tumor emedicine

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