New optical diagnostic tools in renal cell cancer.

In modern medicine the profound use of abdominal imaging has led to a dramatic change of presentation of renal tumors. Smaller tumors and therefore more benign masses are being discovered, and as systemic use of renal mass biopsies is not recommended by the general guidelines, an appropriate tool to assess the biology of renal tumors is highly desirable. Apart from new developments of currently applied diagnostic modalities, several research groups focus on the potential of optical diagnostic techniques to contribute to the diagnostic process of renal tumors. They use the interaction of light with biological tissue to gather information on the optical properties of a tissue sample and therefore providing information on the histological composition of this tissue in a non-invasive manner and in real-time. In this review we provide an overview of novel diagnostic techniques starting with the future of conventional diagnostics like Contrast-enhanced ultrasonography (CEUS) and positron emission tomography-computed tomography (PET-CT) followed by optical technologies that are potentially employed in the nearby future to improve the diagnostic process of renal tumors with a focus on optical diagnostic techniques.