亮細胞腎細胞癌併左心房轉移 – 病例報告

蘇楷森¹、黃子豪^1,2、黃志賢^1,2 

¹臺北榮總泌尿部；²國立陽明交通大學書田泌尿科學研究中心

Clear Cell Renal Cell Carcinoma with Left Atrium Metastasis – A Case Report

Kai-Sen Su¹, Tzu-Hao Huang^1,2, William J. Huang^1,2

¹ Department of Urology, Taipei Veterans General Hospital;

² Department of Urology, School of Medicine and Shu-Tien Urological Science Research Center, National Yang Ming Chiao Tung University

Introduction:

Clear cell carcinoma is the most common pathological feature of kidney malignancy, accounts for 80% of renal carcinomas. One third of patients with clear cell renal cell carcinoma (ccRCC) develop metastatic spread. The common sites of metastasis include the lung, liver, bone, brain, and adrenal gland. We hereby present a rare case of ccRCC with left atrium metastasis.

Case report:

This is a 54-year-old female with no known major disease. Left upper quadrant abdominal pain was firstly noted in October 2019, and computed tomography (CT) revealed a 8.9 cm heterogeneously enhanced lesion at lower pole of left kidney. Tumor growth such as RCC was considered first. Initial full staging showed no evidence of lymphadenopathy or distant organ metastasis. Open partial nephrectomy was arranged later in the same year. Pathology report yielded pT3a clear cell renal cell carcinoma, ISUP3-4, with presence of hilar vein muscular branch invasion. The surgical margin was free and there was no capsule penetration. She was then under regular follow-up at our outpatient department.

She was in stable disease condition until follow-up CT in May 2022 revealed a 4.1x2.9 cm tumor at

left perirenal fascia, which represented a high suspicion of tumor seeding. Open tumor resection was thus performed and metastatic ccRCC was ultimately confirmed on pathology report. According to International Metastatic RCC Database Consortium (IMDC) classification, the patient was calculated to be intermediate risk group. Systemic therapy was not initiated considering the disease status was determined as M1 with no evidence of disease by that time.

Nevertheless, in December 2023, a chest CT scan originally scheduled for routine follow-up of stationary lung nodules revealed dilating filling defect within left atrium and left superior pulmonary vein. Tumor thrombus formation was first considered. Despite the absence of subjective symptoms reported by the patient, she was urgently admitted for further evaluation. Fortunately, she developed dyspnea three days after hospitalization and left atrium tumor removal and lung left upper lobe (LUL) lobectomy were performed on 2023/12/11 by cardiovascular and chest surgeons. The pathology report subsequently confirmed that the left atrium thrombus and the LUL lung nodule were metastatic ccRCCs. Following the surgery, cabozantinib was initiated as treatment for metastatic disease, and the patient continued to undergo close follow-up currently.

Conclusions:

Cardiac involvement in ccRCC commonly manifests as direct tumor thrombus extension into vena cava and right atrium. Cardiac metastasis in the absence of vena cava extension is extremely rare, with less than 15 cases of left atrial metastasis has been reported in the literatures, possibly as a result of lymphatic or lymphohematogenous spread from kidney tumor cells into the thoracic duct and into the superior vena cava (SVC). The optimal treatment strategy for RCC with left heart metastases is unknown owing to the rarity of incidence. Surgical intervention may represent an important role in the palliation of isolated cardiac metastasis, aiming to prevent potentially life-threatening cardiac or thromboembolic complications.