placental site nodule placental site nodule a placental site nodule (psn) is benign remnant from a previous pregnancy. placental site nodulemicrograph of a placental site nodule (top of image). h&e stain. presentation they are typically asymptomatic and found incidentally. pathology psns are intermediate trophoblastic remnants. diagnosis psns are diagnosed by examining the tissue under a microscope, usually obtained with a dilation and curettage. typically, they consist of pink (hyaline) material using the standard stain and contain few cells. bizarre multinucleated cells may be present; however, there is no mitotic activity. the differential diagnosis includes (cervical) squamous cell carcinoma, gestational trophoblastic disease, and exaggerated placental site. prognosis psn are benign. once removed, they do not require any treatment and do not recur.