Endometrial osseous metaplasia presenting as a suspected intrauterine device: diagnostic pitfalls and hysteroscopic management-case report.

Endometrial osseous metaplasia is a rare cause of abnormal uterine bleeding that can mimic an intrauterine foreign body on imaging, leading to diagnostic uncertainty. We report a 48-year-old woman with long-standing abnormal uterine bleeding, prior term vaginal deliveries, and no history of uterine instrumentation or pregnancy loss. Transvaginal ultrasound suggested an intrauterine device. Diagnostic hysteroscopy revealed a firm, whitish, cylindrical lesion with multiple projections anchored at the isthmus and tightly adherent to the myometrium, precluding complete removal due to perforation risk. Representative biopsies were obtained with minimal bleeding. Histopathology confirmed mature bone consistent with endometrial osseous metaplasia, without malignancy or foreign material. The patient experienced symptomatic improvement post-procedure and had an uncomplicated outpatient follow-up. A brief review of the literature indicates that although most cases are linked to prior obstetric events or uterine instrumentation, osseous metaplasia can occur in their absence and may present as an apparent intrauterine device on ultrasound. This report underscores the importance of considering osseous metaplasia in the differential diagnosis of abnormal uterine bleeding and highlights hysteroscopy as the definitive diagnostic and therapeutic approach to obtain targeted tissue and guide management while avoiding unnecessary interventions.