Abstract

Kidney tumours (or kidney tumors), also known as renal tumours, are tumours, or growths, on or in the kidney. These growths can be benign or malignant (kidney cancer).

Presentation

Kidney tumours may be discovered on medical imaging incidentally (i.e. an incidentaloma), or may be present in patients as an abdominal mass or kidney cyst, hematuria, abdominal pain, or manifest first in a paraneoplastic syndrome that seems unrelated to the kidney.

Workup

A CT scan is the first choice modality for workup of solid masses in the kidneys. Nevertheless, hemorrhagic cysts can resemble renal cell carcinomas on CT, but they are easily distinguished with Doppler ultrasonography (Doppler US). In renal cell carcinomas, Doppler US often shows vessels with high velocities caused by neovascularization and arteriovenous shunting. Some renal cell carcinomas are hypovascular and not distinguishable with Doppler US. Therefore, renal tumors without a Doppler signal, which are not obvious simple cysts on US and CT, should be further investigated with contrast-enhanced ultrasound, as this is more sensitive than both Doppler US and CT for the detection of hypovascular tumors.

Classification | Surgical complexity

The RENAL Nephrometry Scoring System is used to measure the complexity of kidney tumors for surgical excision, and is estimated by CT scan as follows:

A higher score indicates a higher difficulty in removing the tumor surgically, potentially making nephrectomy necessary.