Renal oncocytoma: Α case report and literature review

Areti Kalfoutzou1, Cleopatra Rapti2, Vasiliki Lagopulou3, Eleftheria Bagiokou4, Margaritis Tsantopoulos3, Nikolaos Chaleplidis3 and Vasileios Ramfidis2 1 Second Propaedeutic Department of Internal Medicine, Attikon General Hospital, National and Kapodistrian University of Athens, Athens, Greece 2 Department of Medical Oncology, 251 Air Force General Hospital, Athens, Greece 3 Department of Pathology, 251 Air Force General Hospital, Athens, Greece 4 Oncology Unit, 3rd Department of Internal Medicine, Athens General Hospital of Thoracic Diseases “Sotiria”, National and Kapodistrian University of Athens, Athens, Greece Correspondence to: Areti Kalfoutzou, email:[email protected] Keywords: cryoablation; image-guided biopsy; kidney neoplasms; minimally invasive surgery; renal oncocytoma Received: July 23, 2025     Accepted: May 21, 2026     Published: July 02, 2026 Copyright: © 2026 Kalfoutzou et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. ABSTRACT Renal oncocytoma is a rare benign kidney tumor arising from the intercalated cells of the distal renal tubules. These tumors are often asymptomatic and incidentally discovered on imaging. This report presents an 82-year-old female patient with gross hematuria, who was subsequently diagnosed with a small renal oncocytoma. A computed tomography (CT) scan of the abdomen revealed a lesion in the upper left kidney, diagnosed as a renal oncocytoma by histopathological examination of a tissue specimen obtained via a CT-guided biopsy. After multidisciplinary review, the tumor board recommended local treatment with percutaneous cryoablation due to the lesion’s small size and indolent nature. The patient has been on annual follow-up with imaging showing no disease progression over two years. This case highlights the management considerations for renal oncocytoma, particularly in elderly patients, and underscores the role of biopsy and multidisciplinary evaluation in deciding optimal, minimally invasive treatment strategies for benign renal tumors.