Choriocarcinoma isatumorinwhichthepluripotentialneoplasticgermcellsdifferentiateintocellsresemblingplacentaltrophoblasts. Theprimarytumorsoftenaresmallandnonpalpable,eveninpatientswithextensivemetastaticdisease.Thetumoriscomposedofsheetsofsmallcuboidalcytotrophoblast like cells thatareirregularlyintermingledwithorcappedbylarge,eosinophilicsyncytiotrophoblast like cells containingmultipledark,pleomorphicnuclei(
Fig.18.8 ).HCGcanbeidentifiedinthesyncytiotrophoblasticcellsbyimmunohistochemicalstaining.
differentiatealongmultiplesomaticcelllineages.Thesetumors
Fig. 18.7 Yolksactumordemonstratingareasoflooselytextured,micro-cystictissueandpapillarystructuresresemblingadevelopingglomerulus(Schiller-Duvalbodies).
Fig. 18.8 Choriocarcinoma.Bothcytotrophoblasticcellswithsinglecentralnuclei(arrowhead, upper-right) andsyncytiotrophoblasticcellswithmultipledarknucleiembeddedineosinophiliccytoplasm(arrow, middle) arepresent.Hemorrhageandnecrosisareprominent.
http://ebooksmedicine.net ofcartilage.Theymayoccuratanyagefrominfancytoadultlife.Pureformsofteratomaarefairlycommonininfantsandchildren,beingsecondinfrequencyonlytoyolksactumors.Inadults,pureteratomasarerare,constituting2%to3%ofgermcelltumors,andtheremainingtumorsareseenincombinationwithotherhistologictypes.Teratomasarecomposedofaheterogeneous,helter-skeltercollectionofdifferentiatedcellsororganoidstructures,suchasneuraltissue,musclebundles,islandsofcartilage,clustersofsquamousepithelium,structuresreminiscentofthyroidgland,bronchialepithelium,andbitsofintestinalwallorbrainsubstance,allembeddedinafibrousormyxoidstroma (Fig.
18.9 ).Elementsmaybemature(resemblingvarioustissueswithintheadult)orimmature(sharinghistologicfeatureswithfetalorembryonaltissues).In prepubertal males, teratomas are benign, whereas the majority of teratomas in postpubertal males are malignant, being capable of metastasis regardless of whether they are composed of mature or immature elements.
Rarely,non–germcelltumorsmayariseinteratoma—aphenomenonreferredtoasteratoma with malignant transformation. Examplesofsuchneoplasmsincludesquamouscellcarcinoma,adenocarcinoma,andvarioussarcomas.Thesenon–germcellmalignanciesdonotrespondtotherapiesthatareeffectiveagainstmetastaticgermcelltumors(discussedlater);thus,theonlyhopeforcureinsuchcasesresidesinsurgicalresection.
Patients with testicular germ cell neoplasms present most frequently with a painless testicular mass that (unlike enlargements caused by hydroceles) is nontranslucent. Biopsy of a testicular neoplasm is associated with a risk for tumor spillage, which would necessitate excision of the scrotal skin in addition to orchiectomy. Consequently, the standard management of a solid testicular mass is radical orchiectomy, based on the presumption of malignancy. Some tumors, especially nonseminomatous germ cell neoplasms, may have metastasized widely by the time of diagnosis in the absence of a palpable testicular lesion.
Seminomas and nonseminomatous tumors differ in their behavior and clinical course.