A CARE-compliant article: A case report of retroperitoneal endometrial stromal sarcoma with multiple pulmonary metastases and literature review.

Rationale: Endometrial stromal sarcoma is an extremely rare mesenchymal neoplasm occurring in the extrauterine. Retroperitoneal endometrial stromal sarcoma with multiple pulmonary metastases, in particular, is extremely rare.

Patient Concerns: Forty-seven-year-old woman (gravida 3, para 2), was referred to our institution with complaints of fever.

Diagnoses: Ultrasound and computed tomographic imaging of the abdomen identified the presence of masses in the pelvic region. Additionally, computed tomographic scans and X-ray evaluations of the thorax detected dispersed masses in both the lungs and pelvic area. Histopathological analysis of the pelvic region indicated the presence of low-grade endometrial stromal sarcoma. A computed tomography-guided pneumocentesis was conducted to further characterize the pulmonary lesions, confirming the diagnosis of low-grade endometrial stromal sarcoma.

Interventions: The patient underwent tumor resection, subsequent treatment with Medroxyprogesterone acetate for 6 months, received microwave ablation for multiple lung metastases, PARP1 inhibitor for 4 courses, and has been undergoing chemotherapy (epirubicin/ifosfamide) up to the present time.

Outcomes: Partial remission was obtained after the above treatment and this patient is now still alive maintaining for 3 years.

Lessons: The identification and management of this disease remain a significant challenge due to its low prevalence. Further research involving a larger number of cases is necessary to ensure consistency in diagnosis and to establish effective treatment guidelines.