Unexpected rare uterine carcinosarcoma with neuroendocrine differentiation: Reflections on clinical diagnosis and treatment of a case report.

Rationale: Uterine carcinosarcoma (UCS) is a rare and highly invasive malignant tumor.It exhibits an ectopic growth pattern of the uterus,and its histological features are biphasic differentiation of malignant epithelial components (cancer) and malignant mesenchymal components (sarcoma). The pathological pattern of high-component neuroendocrine differentiation is extremely rare. Due to the inherent heterogeneity of tumors, it increases the difficulty of accurate identification and diagnosis. The author introduces a rare case of primary endometrial carcinosarcoma (heterologous) with small cell neuroendocrine carcinoma (SCNEC) components. There is limited literature on this rare pathological differentiation pattern and a lack of guidelines for the best treatment methods, which prompts reflection on the diagnosis, optimal treatment strategies, and how preoperative diagnosis can affect patient prognosis for endometrial carcinosarcoma with neuroendocrine differentiation.

Patient Concerns: The patient is an elderly woman who presents with abnormal vaginal bleeding after menopause. Transvaginal ultrasound examination shows that the uterus is slightly enlarged, and there is a lack of homogeneous echogenicity in the uterine cavity. Subsequently, a hysteroscopic curettage was performed, and a space-occupying lesion was observed on the anterior wall of the uterine cavity.

Diagnoses: Preoperative endometrial biopsy revealed SCNEC of the endometrium. The patient underwent radical hysterectomy, and the postoperative pathological results showed that UCS (heterologous) was accompanied by SCNEC components (about 80%).

Intervention: The patient received radical hysterectomy, followed by adjuvant chemotherapy.

Outcome: After 7 months of follow-up, no tumor recurrence or metastasis was found at the time of writing this article.

Lessons: The histological type of UCS (heterologous) with cell neuroendocrine carcinoma components is rare and highly invasive, with a high misdiagnosis rate in preoperative biopsy. There are currently no effective treatment guidelines for this type of case. The unusual appearance of SCNEC components in this case poses a challenge for both pathologists and surgeon. The rare differentiation pattern of this case exposes the complexity of its management and the necessity of prospective trials to determine the optimal treatment plan.