[Is spontaneous regression of pulmonary metastasis of renal cancer possible? Apropos of a case with review of the literature].

A 64-year-old man was hospitalized with a cancer of the right kidney associated with pulmonary images suggestive of parenchymatous metastases. After nephrectomy and no further treatment, we observed an involution of the images which disappeared completely within a few months and did not recur. Twenty months after the nephrectomy, the chest X-ray remained normal. This case raised the problem of possible spontaneous regression of renal cancer pulmonary metastases. Seventy-two observations were found in the literature: those sufficiently described were analyzed, but certain observations were questionable; a formal pathology diagnosis was only confirmed in two cases in 1959 and in 1977. Because of the rarity of these documented cases and due to the large number of possible causes of round, sometimes transitory, opacities on the chest X-ray, it would appear that one must be very sceptical about the existence of true spontaneous regression of renal cancer pulmonary metastases.