Bilateral Renal Oncocytoma: Active Surveillance Versus Partial Nephrectomy

Abha Sathe,Pranav Sathe,Rithvik Nallapareddy,David Lindars,Tim Grennan

doi:10.7759/cureus.22303

Abstract

Renal oncocytomas (ROs) are benign tumors comprising 16% of renal masses. Due to the overlapping phenotypes seen in RO and chromophobe renal cell carcinoma (RCC) and lack of specific clinical and laboratory characteristics of RO, physicians face a challenge when arriving at a definitive diagnosis of RO. ROs additionally appear indistinct from RCCs on CT scan, contributing further to the difficulty of arriving at a clear diagnosis of RO. This is a case report of a 66-year-old man who presented with flank pain found to be related to bilateral ROs and underwent bilateral partial nephrectomies.ROs are benign small renal masses that often pose a diagnostic challenge since preoperative diagnosis can be difficult to achieve. Given advancements in technology, active surveillance with core renal biopsy is a promising approach to accurately diagnose and manage ROs conservatively. The application of these techniques has wide-reaching implications for patients and physicians by reducing the need for a potentially harmful surgery and creating a cost-effective way to manage a diagnosis.

Highlights

Renal oncocytoma (RO) is a highly differentiated tumor that originates from the distal renal tubule and accounts for 4.3% of solid renal masses and 16% of all renal masses [1,2]
Patients with hybrid tumors often present with constitutional symptoms and gross hematuria when compared to patients with only RO, without coexisting renal cell carcinoma (RCC) [7]
Due to the overlapping phenotypes seen in RO and chromophobe renal cell carcinoma (chRCC) and lack of specific clinical and laboratory characteristics of RO, physicians face a challenge when arriving at a definitive diagnosis of RO [2]

Summary

Introduction

Renal oncocytoma (RO) is a highly differentiated tumor that originates from the distal renal tubule and accounts for 4.3% of solid renal masses and 16% of all renal masses [1,2]. A barrier to the diagnosis and management of ROs is metastasis further complicating the treatment options available to patients with recently diagnosed renal masses. The surgical pathology report of the resected right renal mass confirmed the presence of an RO, showing similar morphology as the resected left mass (Figure 2A, 2B). Postoperative course for both surgeries was uneventful and the patient was discharged within one day of the surgery. With a diagnosis of bilateral ROs, family history of melanoma and prostate cancer, and medical history of actinic keratoses and multiple nonmelanoma skin cancer, the patient sought cancer genetic counseling to evaluate a possible familial disposition to cancer due to BHD syndrome. Our patient tested negative for the FLCN gene, which is found in 84% of BHD-diagnosed patients

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