Diagnostic Approach to Renal Masses

Initial Evaluation

The American Urological Association recommends obtaining high-quality abdominal cross-sectional images to characterize and clinically stage renal masses, complemented by specific laboratory tests and metastatic evaluation when indicated 1, 2, 3
The European Association of Urology suggests that contrast-enhanced CT scans of the chest, abdomen, and pelvis are mandatory for accurate staging of renal cell carcinoma 4, 5
Most renal cell carcinoma cases are initially detected by ultrasonography and subsequently investigated by CT scans 6, 7
Magnetic resonance imaging (MRI) can provide additional information in the investigation of local advancement and venous involvement by tumor thrombus 4, 6

A comprehensive metabolic panel, complete blood count, and urinalysis should be obtained in all patients with suspected renal malignancy 1, 2, 3
Laboratory tests should include serum creatinine, hemoglobin, leukocyte and platelet counts, lymphocyte-to-neutrophil ratio, lactate dehydrogenase, C-reactive protein, and corrected serum calcium 4, 6
The stage of chronic kidney disease should be classified based on eGFR and degree of proteinuria 1, 8

Metastatic evaluation should include chest imaging to assess possible thoracic metastases and careful review of abdominal images 1, 2, 3
Bone scintigraphy or brain CT/MRI is not recommended for routine clinical practice unless indicated by clinical or laboratory signs and symptoms 4, 6

Renal mass biopsy provides histopathological confirmation of malignancy with high sensitivity and specificity 4, 6
Biopsy is especially recommended before treatment with ablative therapies and in patients with metastatic disease before starting systemic treatment 4, 6

Renal cell carcinoma accounts for 90% of renal cancers, with clear cell subtype being the most common (75-80% of cases) 1, 8
More than 50% of renal masses are diagnosed incidentally, with only a minority of patients presenting with symptoms 1, 2, 6
The "classic triad" of symptoms (hematuria, flank pain, and palpable abdominal mass) is more frequently associated with locally advanced or metastatic renal cell carcinoma 1, 2, 3

Genetic counseling should be considered for all patients ≤ 46 years of age and for patients with multifocal or bilateral renal masses, or if personal/family history suggests familial renal neoplastic syndrome 1, 8, 3
Approximately 6-9% of renal cancers have germline mutations in genes associated with cancer predisposition 5
Several autosomal dominant syndromes have been described, including von Hippel-Lindau syndrome, hereditary leiomyomatosis, and renal cell carcinoma, among others 5, 7