Light micrograph of renal medullary interstitial cell tumour. This type of kidney tumour is benign and often seen incidentally as a small nodule. The tumour (right half of image) consists of fibrous stroma (pink to light blue) with small tubular spaces (white). The normal kidney medullary tissue is shown on the left half of the image. Haematoxylin and eosin stained tissue section. Magnification: x100 when printed at 10cm.