Bizarre chorionic-type trophoblast in second-trimester and third-trimester placentas clinicopathologic characterization of a placental pseudoneoplastic lesion

Tricia A. Murdock, Aaron Varghese, Deyin Xing, J. Kenneth Schoolmeester, Caitlin Alexander, Rebecca N. Baergen, Wissam Dahoud, Mark R. Hopkins, Frederic Askin, Russell Vang

Research output: Contribution to journalArticlepeer-review

Abstract

Bizarre (atypical/symplastic) cells have been described in various gynecologic normal tissues and benign neoplasms. This type of bizarre cytologic change is usually an incidental finding and is regarded as a benign process. We describe 17 cases of bizarre chorionictype trophoblast in second-trimester and third-trimester placentas that created concern for an underlying/undersampled or incipient intraplacental trophoblastic neoplasm, predominantly found in intervillous trophoblastic islands (11/17), placental septae (6/17), chorionic plate (1/ 17), and/or the chorion layer of fetal membranes (2/17). The bizarre trophoblastic cells exhibited sheet-like or nested architecture, had a multifocal/patchy distribution, and/or were present as individual cells within hyaline stroma; they were characterized by large nuclei with smudgy chromatin and occasional intranuclear pseudoinclusions. The degree of atypia was classified as mild (0/17), moderate (3/17), or severe (14/17). Mitotic figures and necrosis were not identified. A dual immunohistochemical stain for trophoblast (hydroxyl-delta-5-steroid dehydrogenase) and a proliferation marker (Ki-67), performed in 15 cases, demonstrated 0% to very low proliferative activity within the bizarre trophoblast (0% to 2% [10/15], 3% to 8% [5/15]). Immunohistochemical stains for fumarate hydratase showed intact/retained expression in the bizarre cells in 7 of 7 cases. Clinical follow-up ranged from 1 to 45 months, and all patients were alive and well without subsequent evidence of a gestational trophoblastic or other neoplasms. We conclude that bizarre chorionic-type trophoblast in second-trimester or third-trimester placentas have the potential to mimic an intraplacental trophoblastic neoplasm but are likely a benign degenerative change. This study expands the spectrum of bizarre cells that occur in the gynecologic tract.

Original languageEnglish (US)
JournalAmerican Journal of Surgical Pathology
DOIs
StateAccepted/In press - 2021

Keywords

  • Atypical trophoblast
  • Bizarre
  • Placenta
  • Symplastic
  • Trophoblast

ASJC Scopus subject areas

  • Anatomy
  • Surgery
  • Pathology and Forensic Medicine

Fingerprint

Dive into the research topics of 'Bizarre chorionic-type trophoblast in second-trimester and third-trimester placentas clinicopathologic characterization of a placental pseudoneoplastic lesion'. Together they form a unique fingerprint.

Cite this