Details
Abnormal uterine bleeding.
Placental site nodule is a benign remnant of trophoblastic tissue that fails to regress and is incidentally found many years after pregnancy on endometrial biopsies/curettage. The most common site is the uterine body, however other sites such as fallopian tubes, ovaries, cervix and broad ligament have been found. Grossly they appear as small well-circumscribed yellow-tan nodules, up to 1 cm in size. Microscopically they show well-circumscribed, hyalinized cores surrounded by chorionic-type intermediate trophoblastic cells with abundant clear to eosinophilic cytoplasm. There are rare mitotic figures. The cells in the nodule stain positively for CK18, EMA, inhibin-alpha and PLAP. They stain focally positive for hPL and Mel-CAM; Ki-67 stains 5% of the trophoblastic nuclei. Differential diagnosis includes placental site trophoblastic tumor, which is larger in size, and lacks circumscription and intense hyalinization, however has a high mitotic activity. It stains strongly and diffusely for hPL and Mel-CAM. Another differential is squamous cell carcinoma of the cervix which can also be distinguished by its lack of circumscription and hyalinization, along with high mitotic activity and negative staining for CK18 and inhibin-alpha.