[Secondary tumors of the kidney]

Secondary tumours of the kidney are relatively common. Found at autopsy in approximately 4 per cent of patients dying of malignant disease, they are clinically latent in most instances. Thus in a total series of 295 malignant tumours of the kidney, only 8 were metastases. The primary tumour is most often a bronchial carcinoma, this being confirmed in our series (5 cases). This is followed, in order of decreasing frequency, the breast, stomach, pancreas and stomach. Two of the 8 cases were rarities: a renal metastasis from a meningoblastoma and a metastasis from one tumour to another, a carcinoma of the ovary metastasising to a hypernephroma. The pathogenesis of these secondary tumours leads to the consideration of 2 modes of spread: haematogenous and lymphatic. They present no special clinical features. Intravenous pyelogram reveals the appearances of a malignant tumour mass. Angiography is more informative, the results reflecting the histological nature of the primary tumour. The latter being most frequently a carcinoma, the arteriographic image is one of hypovascularisation, thus differing from a hypernephroma with its rich vascularisation and resembling an infiltrating pelvi-calyceal carcinoma. Histopathological examination is not always conclusive itself. Nephrectomy is effectively only justified if the primary tumour has been or can be successfully treated in the absence of other metastases.