Classification and reporting guidelines for the pathology diagnosis of placenta accreta spectrum (PAS) disorders: recommendations from an expert panel

Abstract

The terminology and diagnostic criteria presently used by pathologists to report invasive placentation is inconsistent and does not reflect current knowledge of the pathogenesis of the disease or the needs of the clinical care team. A consensus panel was convened to recommend terminology and reporting elements unified across the spectrum of PAS specimens (i.e. delivered placenta, total or partial hysterectomy with or without extrauterine tissues, curetting for retained products of conception). The proposed nomenclature under the umbrella diagnosis of Placenta Accreta Spectrum (PAS) replaces the traditional categorical terminology (placenta accreta, increta, percreta) with a descriptive grading system that parallels the guidelines endorsed by the International Federation of Gynaecology and Obstetrics (FIGO). In addition, the nomenclature for hysterectomy specimens is separated from that for delivered placentas. The goal for each element in the system of nomenclature was to provide diagnostic criteria and guidelines for expected use in clinical practice.

Placenta accreta spectrum disorders—experience of management in a German tertiary perinatal centre

“…Newly developed examination protocols for histological preparations include intraoperative evaluation, guided histologic sampling, immediate postoperative examination and dissection guided by preoperative imaging and could more effectively correlate clinical and pathological assessment [41]. In this respect, classification guidelines have been developed by expert panels, which consider not only the classical diagnosis of PAS in case of hysterectomy or partial myometrial resection specimens but also histological findings in delivered placentas and curettings [42]. The establishment of socalled placenta boards is a promising approach, which allows for a regular retrospective evaluation of sonographically, clinically and pathologically diagnosed cases of PAS in an interdisciplinary team [43].…”

Association Between Pre-delivery Coagulation Indicators and Invasive Placenta Accreta Spectrum

“…This study has the following strengths: 1) We included a relatively robust, contemporary cohort of PAS patients with pathologically and/or clinically confirmed PAS diagnoses according to FIGO guidelines. 2 , 26 Patients with coagulopathy or other conditions that may alter the levels of coagulation indicators were excluded. 2) Since this was a single-center study, the patients were likely to receive relatively homogeneous inpatient care and surgical procedures, reducing the likelihood of confounders; 3) Multiple regression model was applied to adjust for known influencing factors of PAS severity; and 4) the association between coagulation test profiles and both PAS severity and blood loss volume during surgery was investigated.…”

“…Patients diagnosed with invasive PAS pathologically and/or clinically between 2018 and 2020 were included. The diagnosis criteria were as follows: (1) pathological criteria 2 : abnormal implantation of chorionic villi upon superficial or deep myometrium without a decidual layer based on microscopic diagnosis; (2) clinical diagnostic criteria: clinical grading was applied according to 2019 International Federation of Gynecology and Obstetrics (FIGO) guidelines 9 : Significant amounts of hypervascularity in the uterine serosa without placenta invasion through the uterine serosa were classified as FIGO grade 2. In FIGO grade 3, placental tissue invades through the surface of the uterus and/or to parametrial regions or adjacent organs.…”

One step closer to reducing PAS morbidity

“…Similar to FIGO, others have recognized the need for common definitions and language; as a result, international consensus on ultrasound markers and pathologic definitions have also been recently developed. [6][7][8] While PAS is not a malignancy, either biologically or histologically, some similarities exist with regard to standardization of nomenclature, and the obstetrics community may benefit from lessons learned in the world of cancer research. The ideal PAS grading classification would predict and prognosticate maternal outcomes, akin to cancer staging.…”

“…This grading system was greatly needed, as it provides standardization that allows for comparison of findings from various studies and hopefully paves the way for conclusions that are clear, data‐driven and consistent. Similar to FIGO, others have recognized the need for common definitions and language; as a result, international consensus on ultrasound markers and pathologic definitions have also been recently developed 6–8 …”