Rare uterine tumor with bone-like differentiation reported in 72-year-old woman

The case, published as a case report in BMC Women’s Health, involves a 72-year-old postmenopausal woman who sought care for vaginal bleeding.

Uterine carcinosarcoma is a malignant tumor with two distinct components, a carcinoma and a sarcoma, growing side by side. The subtype reported here carries heterologous osteosarcomatous differentiation, meaning the sarcomatous part forms osteoid or bone tissue, a feature that is exceedingly uncommon and, according to the authors, makes preoperative diagnosis challenging.

Transvaginal ultrasonography in this patient revealed a hypoechoic intracavitary lesion containing calcified foci and punctate blood flow signals. A metallic intrauterine device was also present within the uterine cavity.

To clarify the diagnosis, the clinical team performed hysteroscopic resection of the lesion and removal of the intrauterine device. Histopathological examination of the resected tissue, together with immunohistochemistry, supported a diagnosis of uterine carcinosarcoma with heterologous osteosarcomatous differentiation.

Because the tumor contained bone-forming tissue, the clinicians needed to exclude a primary bone tumor before proceeding. The patient therefore underwent bone scintigraphy and postoperative pelvic magnetic resonance imaging, which also served to assess the local extent of disease.

Definitive surgical pathology subsequently demonstrated residual tumor in the lower uterine corpus, with myometrial invasion of less than half the myometrial thickness. Under the FIGO 2023 staging system, the final pathological stage was assigned as IIC.

After the definitive operation, the patient completed two cycles of adjuvant chemotherapy and one session of radiotherapy.

At the last follow-up on September 23, 2026, no definite evidence of recurrence or metastasis was identified on imaging studies. The report notes this as the status at a single follow-up time point, not a long-term outcome.

The authors draw a practical diagnostic lesson from the case. They suggest that uterine carcinosarcoma with heterologous osteosarcomatous differentiation should be considered in the differential diagnosis of calcified intrauterine lesions in postmenopausal women with abnormal uterine bleeding. At the same time, they emphasize that such imaging findings are nonspecific, and that definitive diagnosis still depends on pathological examination.

As a single-patient case report, the findings describe one clinical course rather than a treatment comparison or a population-level result. The report is published open access, with the article shared early to provide faster access to peer-reviewed, accepted research, and it remains subject to further edits before the final version of record.

Subject of Research: A rare case of uterine carcinosarcoma with heterologous osteosarcomatous differentiation in a postmenopausal woman

Article Title: Uterine carcinosarcoma with heterologous osteosarcomatous differentiation: a case report

Article References: Chang, S., Zhao, J., Zhou, L., Tang, C., & Yang, R. (2026). Uterine carcinosarcoma with heterologous osteosarcomatous differentiation: a case report. BMC Women's Health. https://doi.org/10.1186/s12905-026-05021-w

Image Credits: AI Generated

DOI: 10.1186/s12905-026-05021-w

Keywords: uterine carcinosarcoma, osteosarcomatous differentiation, case report, postmenopausal bleeding, hysteroscopy, FIGO 2023 staging, bone scintigraphy, pelvic MRI, adjuvant chemotherapy, BMC Women's Health, gynecologic oncology, intrauterine device