An unusual uterine papillary serous carcinoma with post therapy disseminating metastasis presenting as primary renal malignancy: a case report.

Introduction: Uterine papillary serous carcinoma (UPSC) is a highly aggressive endometrial carcinoma that often presents as a high-stage disease. UPSC has a high propensity for metastasis and recurrence, even with little or no myometrial invasion. It usually metastasizes to the pelvis, retroperitoneal lymph nodes, upper abdomen, or peritoneum. However, renal metastasis of UPSC is extremely rare. Case presentation: The authors reported a unique UPSC case in a 75-year-old unmarried woman. Twenty years ago, she had a history of right breast cancer and underwent a modified radical mastectomy. Three years ago, she was diagnosed with endometrial carcinoma, and six courses of chemotherapy and radiotherapy were administered. Computed tomography and retrograde pyelography revealed a right renal pelvic tumor, and a right nephroureterectomy was performed. Renal metastatic UPSC was diagnosed. The patient was administered adjuvant chemotherapy. Clinical discussion: Metastatic UPSCs initially presenting at distant sites are uncommon manifestations. This tumor should be differentially diagnosed in patients presenting with metastatic high-grade serous papillary carcinoma of unknown primary origin. Conclusion: Diagnosing metastatic renal UPSC, based on preoperative and imaging examinations, is often challenging. Thus, a review of the past history, histopathology, and immunohistochemical evaluation plays a crucial and valuable role in the definite and differential diagnosis of this tumor type.