Kidney tumour. Coloured computed tomography (CT) scan showing an axial section through the abdomen of a patient with a kidney tumour (lower left). The front of the body is at top in this view from below. The two kidneys (dark red) are seen either side of the central spine (black, lower centre). Here, in the upper abdomen, the ribs (black) still enclose the body. The tumour distorts the shape of the right kidney (lower left). The well-defined orange mass in the left kidney is a cyst. Tumours are abnormal growths that are benign or malignant (cancerous). A cyst is an abnormal fluid-filled sac. The liver (blue) is at centre left.