Placental Site Nodule
Also written as: PSN
A benign, hyalinised remnant of intermediate trophoblastic cells incidentally found in endometrial or cervical curettage specimens, representing a retained focus of implantation-site trophoblast.
Full Definition
A placental site nodule (PSN) is a small, well-circumscribed, hyalinised lesion composed of implantation-site intermediate trophoblastic cells, typically detected as an incidental finding in endometrial or endocervical curettings from women of reproductive age. The cells are embedded in abundant eosinophilic hyaline matrix and show low proliferative activity (Ki-67 <10%), distinguishing PSN from the malignant epithelioid trophoblastic tumour (ETT). Although PSN is a benign lesion with no clinical consequence, it must be distinguished from ETT and placental site trophoblastic tumour (PSTT) in pathology reports. In paediatric pathology, PSN is encountered when examining placental and abortion specimens. Editors should confirm correct spelling: 'placental' not 'placenta'.
Usage
Usage note: Always use the adjective form 'placental' not the noun 'placenta' as a modifier. Distinguish clearly from placental site trophoblastic tumour (PSTT) and epithelioid trophoblastic tumour (ETT).
In Context
- "Curettage specimen sections demonstrated a placental site nodule with prominent hyalinisation and no evidence of atypia." — Gynaecological pathology report
- "The editor queried whether 'placenta site nodule' in the draft was a transcription error for 'placental site nodule'." — Proofreading query