同步異質性腎細胞癌：單側多發性腎臟腫瘤的診斷分型與保留腎元手術的臨床挑戰

吳冠儒¹、李致樵¹

¹台灣基督長老教會馬偕醫療財團法人馬偕紀念醫院泌尿科

Synchronous Dual-Histology Renal Cell Carcinoma (Papillary and Clear Cell Types) within a Single Kidney Complicated by Post-Surgical Pseudoaneurysm: A Case Report

Kuan-Ju Wu¹, Chih-Chiao Lee¹

¹Department of Urology, MacKay Memorial Hospital, Taipei, Taiwan

Introduction –

Renal Cell Carcinoma (RCC) is the most prevalent malignancy of the kidney. However, the concurrent presence of two distinct histological subtypes - specifically Clear Cell RCC and Papillary RCC - as synchronous multifocal tumors within the same renal unit represents an exceedingly rare clinical scenario. This report details the diagnostic complexities and specialized management required for this condition in a medically challenging patient, emphasizing the need for robust surgical planning and the management of critical postoperative complications.

Case presentation –

A 51-year-old male with significant underlying comorbidities, including coronary artery disease (CAD), presented with non-specific symptoms including general malaise and mild right upper quadrant abdominal pain. An incidental finding on a screening echo revealed a 2.3 cm cystic and heterogeneous lesion in the left kidney. Subsequent CT and MRI confirmed two discrete masses in the left kidney lower pole: a medial tumor measuring up to 4.2 cm and a lateral tumor measuring up to 2.6cm. Following a CT-guided biopsy which suggested malignancy, the patient underwent a Robotic Left Laparoscopic Partial Nephrectomy on October 3, 2025, to achieve oncological control while maximizing nephron preservation.

Result –

The definitive pathological analysis confirmed the rare diagnosis of synchronous multifocal RCC with dual histologies. The larger medial lesion was classified as Papillary Renal Cell Carcinoma, type 2, measuring 4.2 cm, staged as pT1b (TNM 8th Edition). The smaller lateral lesion was diagnosed as Clear Cell Renal Cell Carcinoma, measuring 2.6 cm, staged as pT1a. Both tumors were limited to the kidney, and all surgical margins were uninvolved by carcinoma. Postoperatively, the patient developed gross hematuria. Emergency angiography identified a 2.4 cm pseudoaneurysm with an associated Arteriovenous (AV) fistula in the inferior portion of the left kidney. This critical vascular complication was successfully treated via Transarterial Embolization (TAE).