<prompt> Schiller- Duval bodies are seen inTeratomaSeminomaYolk sac tumourChorio - carcinoma  <response>: Yolk - sac tumour 736 - HM 5th 692- Basic pathology 8thYOLK-SAC-TUMOUR synonyms - Endo dermal sinus tumurs, orchioblastoma, Infantile embryonal carcinoma This characteristic tumour is the most common testicular tumour of infants and young children up to the age of 4 years AFP levels are elevated in 100 cases of yolk sac tumoursMicroscopic - The tumour cells may form distinctive perivascular structures resembling the yolk sac or endodermal sinuses of the rat placenta called Schiller - Duval bodies There may be presence of both intracellular and extra cellular PAS positive hyaline globulesCHORIOCARCINOMA - ME - Characteristic feature is the identification of intimately related syncytiotrophoblast and cyto trophoblast without formation of definite placental type villiTERATOMA - Honey - combed areas and foci of cartilage and boneSEMINOMA - Commonest malignant tumour of the testis and corresponds to dysgerminoma in femaleMF. shows lobules of monomorphic seminoma cells separated by delicate fibrous stroma containing lymphocytic infiltration 