Clinical and pathologic features of initial metastatic presentations of renal cell carcinoma

The problem of metastasis from an occult renal cell carcinoma is illustrated by 2 case reports, one involving an expectorated endobronchial tumor and the other a solitary costal lesion. The absence of clinical or laboratory findings suggestive of a primary renal tumor does not rule out this diagnosis and a high level of suspicion must be maintained. Application of histochemical techniques in the examination of a lesion which is not known to be metastatic may reveal its true nature. The clinical significance of the solitary metastasis from a renal cell carcinoma is discussed.