Superficial peritoneal endometriotic lesions are histologically diverse and rarely demonstrate menstrual cycle synchronicity with matched eutopic endometrium

Eliza M Colgrave, E M Colgrave, Colgrave EM, S Bittinger, Bittinger S, Sophie Bittinger, M Healey, Martin Healey, Healey M, Uri P. Dior, Dior UP, U P Dior, Peter A. W. Rogers, P A W Rogers, J R Keast, Janet R. Keast, J E Girling, Jane E. Girling, S J Holdsworth-Carson, Holdsworth-Carson SJ, Sarah J. Holdsworth‐Carson
Human Reproduction · 2020 · vol. 35(12) , pp. 2701–2714 · doi:10.1093/humrep/deaa249 · PMID:33300558 · W3112883773
Observational OA: closed CC0 ⤵ 36 in-corpus citations
View on OpenAlex View on PubMed View at publisher
⚙ AI-generated summary by gemini-2.5-flash-lite, 2026-06-09 ⓘ

Superficial peritoneal endometriotic lesions exhibit significant histological variability, with only a small fraction showing menstrual cycle synchronicity with matched eutopic endometrium.

One-sentence paraphrase of the abstract; not a substitute for reading it. No clinical advice. How this works

Abstract

STUDY QUESTION: Do menstrual cycle-dependent changes occur in the histological appearance of superficial peritoneal endometriotic lesions, and are they equivalent to those observed in the eutopic endometrium? SUMMARY ANSWER: Only a small subset of superficial peritoneal endometriotic lesions exhibits some histological features in phase with menstrual cycle-related changes observed in eutopic endometrium. WHAT IS KNOWN ALREADY: Endometriotic lesions are frequently described as implants that follow menstrual cycle-related changes in morphology, as per the eutopic endometrium. This concept has been widely accepted despite the lack of conclusive published evidence. STUDY DESIGN, SIZE, DURATION: This was a retrospective cohort study of 42 patients, from across the menstrual cycle, with surgically and histologically confirmed endometriosis. Patients were a subset selected from a larger endometriosis study being conducted at the Royal Women's Hospital, Melbourne since 2012. PARTICIPANTS/MATERIALS, SETTING, METHODS: Histological features of epithelium, stroma and gland morphology were examined in haematoxylin and eosin stained sections of superficial peritoneal endometriotic lesions and matched eutopic endometrium (menstrual: n = 4, proliferative: n = 11, secretory: n = 17, hormone-treated: n = 10). At least two biopsies (average = 4, range = 2-8 biopsies) and a matched endometrial sample were analysed for each patient and results were presented per endometriotic gland profile (n = 1051). Data were analysed using mixed effects logistic regression to account for multiple patients and multiple endometriotic biopsies, each with multiple endometriotic gland profiles. This model also enabled analysis of endometriotic lesions versus eutopic endometrium. MAIN RESULTS AND THE ROLE OF CHANCE: There was considerable inter- and intra-patient variability in the morphology of superficial peritoneal endometriotic lesions. Menstrual cycle-associated changes were only observed for some features in a subset of endometriotic gland profiles. The proportion of endometriotic gland profiles with epithelial mitoses significantly increased in the proliferative phase (18% of gland profiles) relative to the menstrual phase (0% of endometriotic gland profiles) (odds ratios (OR) 9.30; 95% confidence intervals (CI) = 3.71-23.32; P < 0.001). Fewer blood-filled gland lumens were observed in the secretory phase (45% of endometriotic gland profiles) compared to the menstrual phase (67% of endometriotic gland profiles) (OR, 0.30; 95% CI = 0.11-0.79; P = 0.015). The features of the eutopic endometrium analysed in this study did not reflect the results in matched endometriotic lesions (P > 0.05). LARGE SCALE DATA: Not applicable. LIMITATIONS, REASONS FOR CAUTION: This study focused on features observed in sections of superficial peritoneal lesions and these may differ from features of deep infiltrating endometriosis or ovarian endometriomas. Cycle phases were limited to menstrual, proliferative and secretory phases to allow appropriate statistical modelling. WIDER IMPLICATIONS OF THE FINDINGS: This study highlights heterogeneity in the histological characteristics of superficial peritoneal lesions. It challenges the assumption that lesion morphology consistently reflects menstrual cycle-associated changes. STUDY FUNDING/COMPETING INTEREST(S): Research reported in this publication was supported in part by National Health and Medical Research Council (NHMRC) project grants GNT1012245, GNT1105321 and GNT1026033 (P.A.W.R., J.E.G. and S.J.H.-C.). There are no competing interests.

My notes (saved in your browser only)

Condition tags

endometriosisdie_deep_infiltrating

MeSH descriptors

Endometriosis Endometriosis Peritoneal Diseases Peritoneal Diseases Endometrium Endometrium Female Female Humans Humans Menstrual Cycle Menstrual Cycle Retrospective Studies Retrospective Studies

Citation neighborhood (2-hop)

Papers in the corpus that this work cites (lower rings, blue) and that cite this one (upper rings, green). Dot size scales with the paper's in-corpus citation count — bigger dot = more influential within the endo/adeno field. Click a dot to open that paper. Outer rings show 2-hop neighbours — papers reached through the immediate citers/citees. [ collapse to 1-hop ]

References (60)

Cited by (36)

Source provenance

europepmc
last seen: 2026-10-11T09:27:45.537177+00:00
openalex
last seen: 2026-06-10T17:14:06.276822+00:00
pubmed
last seen: 2026-10-08T21:29:19.503995+00:00
License: CC0 · commercial use OK