Low-Grade Uterine Adenosarcoma with Overexpression of MDM2 and CDK4 by Immunohistochemistry: A Case Report and Literature Review.

Introduction: Uterine adenosarcoma (UA) is a rare malignant mesenchymal neoplasm characterized by benign epithelial and malignant stromal components. Comprehensive genomic profiling has identified a high frequency of murine double-minute type 2 (MDM2) and cyclin-dependent kinase 4 (CDK4) amplification in UA. However, the significance of these genetic alterations in tumor biology remains poorly understood. This report presents a case of UA with immunohistochemically positive MDM2 and CDK4 expression.

Case presentation: The patient was a 72-year-old woman with a history of genital bleeding. Magnetic resonance imaging revealed an 11 × 5 × 7 cm mass in the endometrial cavity, extending into the uterine cervix. Biopsy of the tumor showed no malignant findings. The patient underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy. Microscopically, the tumor consisted of benign glandular epithelial components and low-grade sarcoma. The diagnosis was UA stage IA, pT1aNxM0. No sarcomatous overgrowth and no myometrial or lymphovascular invasions were observed. Immunohistochemistry confirmed MDM2 and CDK4 expression in the mesenchymal tissue. No recurrence was observed 12 months post-surgery.

Conclusion: The pathological diagnosis of UA was based on histomorphological features. This study demonstrates that immunohistochemistry for MDM2 and CDK4 can help elucidate the molecular genetic features of UA. Further studies are needed to correlate the expression of these genes with the biological behavior of UA.