Incidence, Prognosis, and Management of Occult Endometrial Carcinoma After Hysterectomy for Benign Disease: A Systematic Review and Meta-Analysis

Background/Objectives: Occult endometrial carcinoma, incidentally diagnosed after hysterectomy for presumed benign disease, raises concerns regarding its incidence, the prognostic effects of minimally invasive surgery and morcellation, and subsequent management. This systematic review synthesized the available evidence and performed meta-analysis where appropriate. Methods: PubMed, Scopus, and the Cochrane Central Register were searched using a sensitivity-tested strategy. After de-duplication and screening, 76 studies met the eligibility criteria. Incidence was pooled using a random-effects meta-analysis of proportions with the Freeman–Tukey double-arcsine transformation. Subgroup analyses examined surgical contexts, including hysterectomy for benign disease, morcellation-specific cohorts, and pelvic organ prolapse surgery. Survival and management outcomes were synthesized narratively. Results: Among 68 studies with extractable denominators, the pooled incidence (proportion of hysterectomies with carcinoma on final pathology) of occult endometrial carcinoma following hysterectomy for benign disease was 0.33% (95% prediction interval, 0.04–0.87%). Incidence was lowest in selected morcellation cohorts (0.22%) and higher in unselected benign hysterectomy cohorts (0.33%) and prolapse populations (0.43%; test for subgroup differences, p = 0.03), with substantially higher rates among older patients. The pooled incidence of occult uterine malignancies, including sarcoma, was 0.54%. For endometrial carcinoma specifically, the limited observational evidence did not demonstrate a statistically significant association between power morcellation or laparoscopic surgery and poorer survival, although confidence intervals were wide. However, morcellation was associated with increased mortality among patients with uterine sarcoma. Occult endometrial carcinomas were predominantly early-stage and low-grade, with 81.8% classified as International Federation of Gynecology and Obstetrics IA, and approximately 91% achieving 5-year overall survival. In a small series of selected high-risk patients, completion staging resulted in upstaging in 25% and informed adjuvant treatment decisions. Limited observational data did not demonstrate a statistically significant survival benefit of complementary lymphadenectomy, although estimates were imprecise. Conclusions: Occult endometrial carcinoma occurs in approximately 0.2–0.4% of hysterectomies performed for benign disease, with a pooled incidence of 0.33% and higher rates among older patients. The limited observational evidence did not demonstrate a statistically significant association between minimally invasive surgery or morcellation and poorer survival, but estimates were imprecise; wide confidence intervals and potential residual confounding preclude conclusions regarding oncologic safety. Overall prognosis was favorable. These findings support age-informed preoperative counseling and appropriate endometrial evaluation, with individualized consideration of re-staging when occult carcinoma is identified.