Renal oncocytoma in a kidney transplant patient: the imaging features on contrast-enhanced ultrasonography (CEUS): a case report

Abstract Renal oncocytoma is an infrequently reported renal neoplasm, often asymptomatic, which usually behaves as a benign entity and is identified accidentally on radiological imaging. Transplant patients under long-term immunosuppressive drugs have a high prevalence of cancers, such as skin cancers, lymphoproliferative disorders, and renal carcinomas. We present a case report of an asymptomatic renal oncocytoma in a kidney transplant recipient presenting persistent hematuria. The features of computed tomography and contrast-enhanced ultrasound (CEUS) are presented. This was the first time we used CEUS in a transplant kidney recipient presenting a renal mass, allowing the real-time visualization of contrast-enhancement patterns during all vascular phases for the differential diagnosis of renal tumors. Although the pattern of intense vascularization could mislead to an early judgment as a malignant lesion, it could help to exclude other renal lesions without inducing nephrotoxicity.

摘要：肾嗜酸细胞瘤（Renal oncocytoma）是一种较为罕见的肾脏肿瘤，通常无明显临床症状，多呈良性病程，且常于影像学检查中偶然被发现。长期接受免疫抑制药物治疗的移植受者，罹患皮肤癌、淋巴增生性疾病及肾癌等肿瘤的风险显著升高。本文报告1例肾移植受者罹患无症状性肾嗜酸细胞瘤，却表现为持续性血尿的病例，并呈现该病例的计算机断层扫描及超声造影（contrast-enhanced ultrasound, CEUS）影像学特征。这是本团队首次将超声造影应用于伴肾占位的肾移植受者中，可实时显示全血管时相的造影强化模式，助力肾脏肿瘤的鉴别诊断。尽管该病灶的高血管化特征可能会误导早期判断为恶性病变，但该检查手段可在不引发肾毒性的前提下，帮助排除其他肾脏病变。