腎臟鱗狀細胞癌之診斷困境：一例模擬婦科腫瘤的罕見病例

沈毓明、石宏仁

彰化基督教醫院泌尿外科

A Diagnostic Challenge of Renal Squamous Cell Carcinoma Mimicking a Gynecologic Mass: A Rare Case Report

Yu-Ming Shen, Hung-Jen Shih

Division of Urology, Department of Surgery, Changhua Christian Hospital

Introduction

Renal squamous cell carcinoma (SCC) is a rare and aggressive malignancy, accounting for less than 1% of all renal cancers. Most commonly associated with chronic kidney irritation, such as from calculi or infections, SCC often presents with non-specific symptoms that complicate early diagnosis. This paper discusses a unique case of renal SCC located in the pelvis, which mimicked a gynecological tumor, illustrating the diagnostic challenges in distinguishing renal and reproductive system tumors.

Case presentation

An 80-year-old female patient presented to our urology clinic with a chief complaint of a self-palpated lower abdominal mass. Pelvic Magnetic Resonance Imaging (MRI) demonstrated a well-circumscribed mass measuring 12 cm in diameter, characterized by heterogeneous signal intensity and minimal contrast enhancement, initially suggesting an ovarian or adnexal neoplasm (Figure 1). Comprehensive tumor marker analysis revealed normal levels of alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), cancer antigen 125 (CA 125), and cancer antigen 19-9 (CA 19-9), while squamous cell carcinoma (SCC) antigen was notably elevated.

The patient underwent surgical exploration, during which the uterus and bilateral adnexa were found to be unremarkable. The excised specimen revealed a cystic mass with extensive fibrous adhesions on its external surface (Figure 2). Upon dissection, abundant grayish-white keratin-like material was observed within the lesion (Figure 3). Histopathological examination confirmed the diagnosis of primary renal pelvis squamous cell carcinoma with invasion into the renal parenchyma, originating from the left kidney. The patient's postoperative course was uneventful, and she continues to receive regular surveillance at our outpatient department.

Discussion

Renal SCC is closely linked to chronic inflammation and irritation from conditions like recurrent renal stones, hydronephrosis, and infections. These factors can lead to squamous metaplasia and increase the risk of malignant transformation in the renal epithelium. In this case, the tumor's location in the renal pelvis and its imaging characteristics closely resembled those of a gynecologic tumor, which led to initial misdiagnosis. SCC of the renal pelvis, though rare, presents considerable diagnostic challenges, as its radiological features often overlap with other renal conditions, such as xanthogranulomatous pyelonephritis and tuberculosis. Advanced imaging techniques, especially contrast-enhanced CT, may help identify unique features like hydronephrosis, calcifications, or irregular pelvic masses; however, a definitive diagnosis usually requires histopathological examination following nephrectomy.

Given the aggressive progression and poor prognosis associated with renal SCC, early detection and accurate diagnosis are critical but challenging. This case underscores the importance of including renal SCC in the differential diagnosis for patients with longstanding renal calculi and atypical pelvic masses, especially when presenting with symptoms more typical of gynecologic malignancies.