Choriocarcinoma histopathology

(A) Hysterectomy was performed for post-gestational choriocarcinoma. Note the sheet-like proliferation of choriocarcinoma tumor cells (C) replacing the endometrium and pushing into the myometrium (M). Tumor-associated hemorrhage (H) is visible. The lack of chorionic villi distinguishes this trophoblastic proliferation from complete hydatidiform mole.

(B) At higher magnification, one can see two populations of highly atypical trophoblasts: mononuclear cytotrophoblasts (C) and multinuclear syncytiotrophoblasts (S). The syncytiotrophoblasts have amphophilic (purplish) cytoplasm and produce beta-hCG (not shown). Compare the size of the malignant trophoblast cells and their atypical nuclei with red blood cells and neutrophils scattered throughout the panel (unmarked). Mitotic figures (arrows) are frequent.