Intermediate trophoblast is a distinct subtype of trophoblastic tissue that arises from the cytotrophoblast.
It is sub-categorized by location:
Villous intermediate trophoblast:at anchoring villi of trophoblastic columnImplantation site intermediate trophoblast:at implantation site (or basal plate), differentiated from villous intermediate trophoblastChorionic-type intermediate trophoblastat chorionic laeve of fetal membrane, differentiated from villous intermediate trophoblastThe function of the implantation site intermediate trophoblast is to anchor the placenta to the maternal tissue.
Villous intermediate trophoblastpolyhedral and uniform nucleiprominent cell border; abundant eosinophilic to clear cytoplasmcohesive growthImplantation site intermediate trophoblastpleomorphic irregular nuclei, large and hyperchromatic, may multinucleationabundant eosinophilic to amphophilic cytoplasminfiltrative growth (splitting muscle, replacing vascular wall ...etc)Chorionic-type intermediate trophoblastround to polyhedral nuclei, may multinucleationabundant eosinophilic to clear cytoplasmcohesive growthIntermediate trophoblasts are thought to be the cell of origin for:
Exaggerated placental site (EPS): implantation site ITPlacental site nodule (PSN): chorionic-type ITPlacental site trophoblastic tumour (PSTT): implantation site ITEpithelioid trophoblastic tumour (ETT): chorionic-type IT
