Introduction: An overview of the history of the evolving diagnostic modalities of renal masses is paramount to understanding the changing landscape of the management of small renal masses (SRMs) and the current utility of renal mass biopsies (RMBs).
Methods: We performed a comprehensive literature search in PubMed. Abstracts were reviewed and articles were selected based on relevance.
Results: Imaging plays a key role in the evolution of the diagnosis of renal masses. After the development of the X-ray in 1896, urologists performed retrograde pyelography using sodium salts in which renal masses were identified by their calyceal distortion. In 1923, Osborne reported kidney opacification in patients while treating syphilis with intravenous (IV) sodium iodide. IV pyelograms were used to differentiate benign and malignant renal masses. In 1953 Seldinger published his technique using a femoral artery catheter to perform renal angiography. Differentiating a cyst from a tumor using angiography was 75-95% accurate and was routinely used for surgical planning with the addition of epinephrine to improve tumor visualization. In the 1970s ultrasound was routinely used to distinguish cysts from solid masses until cross sectional imaging was developed soon after. In 1984 Lang combined computed tomography (CT) and angiography to improve renal mass staging, and in 1986 Bosniak developed his classification of cystic renal masses. CT altered the diagnosis and management of renal masses. Between the 1980s to 2000s there was a 52% increase in incidence. Increased SRMs caused growing concern for over-diagnosis and over-treatment. In 1995 Bosniak published his observations of slow growth in SRMs, and studying Von Hippel-Lindau (VHL) syndrome gave experience with safely surveilling SRMs <3 cm. It was not until 2008 when Jewett et. al. proposed active surveillance (AS) for SRMs in elderly patients. Since then, two AS databases have revealed no difference in 5-year cancer specific survival. These results have allowed AS to be a more widely accepted management and renewed an interest in RMBs. RMBs initially had limited indications including diagnosis of suspected lymphoma, metastasis, or inflammatory processes. Controversy over their accuracy, complications, and non-diagnostic rate precluded widespread use. Since 2001, multiple studies have demonstrated an 88-96% accuracy and a low complication rate using core needle biopsies. Although, future development of targeted non-invasive imaging modalities and biomarkers may give RMBs a transient role in management paradigms.
Conclusions: Imaging has altered the diagnosis of renal masses.
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