Solitary pulmonary metastases from renal cell carcinoma: comparison of high-resolution CT with pathological findings.

Purpose: The aim of this study was to examine the radiographic features of solitary pulmonary metastases from renal cell carcinoma by comparing high-resolution CT (HRCT) findings with histopathological observations.

Materials And Methods: Three thoracic radiologists retrospectively reviewed HRCT findings from eight patients who underwent surgery on the basis of the diagnosis of solitary pulmonary metastatic renal cell carcinoma. The histopathological diagnoses for six of these eight lesions were metastases from clear cell carcinoma of the kidney, one case was a metastasis from papillary renal cell carcinoma, and the remaining case was a metastasis from a poorly differentiated carcinoma including predominantly spindle cells, papillary cells, and clear cells.

Results: The HRCT findings of all cases of clear cell carcinoma showed solid nodular lesions without ground-glass attenuation (GGA). The HRCT findings for one case of papillary renal cell carcinoma showed a lobulated nodule with a small amount of GGA in an area in the periphery and an air bronchogram. The HRCT findings of the remaining case of poorly differentiated carcinoma showed an ill-defined nodule with a GGA area and pleural indentations.

Conclusion: In brief, solitary pulmonary metastases from renal cell carcinoma may present as a smoothly marginated nodule, lobulated nodule, or a nodule with peripheral GGA.