Pretreatment Assessment of Occult Uterine Sarcoma Risk Before Uterus-Preserving Treatment of Presumed Fibroids: A Narrative Review

Among uterus-preserving treatments for presumed fibroids, only myomectomy yields a specimen. Occult uterine sarcoma is uncommon, but leiomyosarcoma is clinically aggressive and seldom recognised before treatment. This narrative review examines what pretreatment assessment can and cannot establish. Literature from PubMed/MEDLINE, Scopus, Web of Science, Embase, and the Cochrane Library was synthesised narratively. Reported frequencies of unexpected sarcoma differ between clinical populations, mostly from 0.1% to 0.4%, and rise with age. Other predisposing factors are imprecisely quantified; genome-wide association data do not discriminate sarcoma from leiomyoma. Separate meta-analyses, largely of retrospective, enriched studies, report higher accuracy for magnetic resonance imaging (MRI), including diffusion-weighted sequences, than for ultrasound, by indirect comparison. Serum markers, composite scores and circulating nucleic acids remain supportive or investigational; directed biopsy lacks validation in unselected populations. In all-sarcoma scenarios, published likelihood ratios indicate that a negative MRI lowers, but does not eliminate, the probability of sarcoma; an exploratory, assumption-dependent reconstruction from a consecutive cohort illustrates their uncertain transportability. No available test reliably excludes sarcoma; after specimen-free therapy, a missed sarcoma may remain unrecognised until reassessment. We propose a conceptual framework, not a validated decision rule, that considers absolute residual risk alongside the specimen status of the chosen treatment.