Renal Carcinoma: How it Metastasizes

Abstract

The renal cell carcinoma, known also as hypernephroma and Grawitz tumor, is one of the present-day entities replacing syphilis as a medical enigma. The disorder presents occasionally with anemia, erythremia, pyrexia of unknown etiology, hypercalcemia, or salt-losing syndrome and demands respect (12). For the radiologist, too, there are many confusing aspects concerning the sites and time of appearance of metastases, difficult not only to predict, but also to explain. Because a better understanding of the modes of spread could help in earlier diagnosis, rationale of treatment, and method of follow-up, 152 cases of proved hypernephromas, including 49 followed until necropsy, were studied retrospectively. Spread via the lymphatics and the paravertebral plexus of veins was found to playa more important role than generally appreciated. Lymph Node Metastases Nodes of the renal pedicle and paraaortic areas are sometimes involved at surgery, but little attention is focused on this in subsequent patient follow-up. In 12 of the 152 patients in this series, palpable or roentgenologically obvious supradiaphragmatic node metastases developed, with pathologic verification in all but 2. Eleven had mediastinal adenopathy including carinal, hilar, or paratracheal areas, and 5 had left lower anterior cervical or supraclavicular adenopathy (the socalled “sentinel” nodes). Although in all 12 concomitant lung seeding occurred, this was not always radiologically visible or even macroscopically apparent at necropsy. This gross central adenopathy, often with small peripheral lesions, as well as the left neck node involvement suggest that the hypernephroma is like other infradiaphragmatic cancers in its use of lymphatics for spread. Figure 1 shows a right hilar lesion causing peripheral atelectasis; Figure 2 reveals what is lymphogenous spread radiologically, a pattern observed in 3 patients. These should be contrasted with the typical “cannonball” lesions (Fig. 3) discussed below. One case was of special interest—the patient died from unrelated causes thirteen years post-nephrectomy, and necropsy confirmed a 3 ern carinal metastasis and a 1 ern upper lobe nodule. Lung Metastases Showers of tumor emboli traveling through the inferior vena cava result in the multiple cannonball metastases so characteristic of this lesion (Fig. 3). Forty cases disclosed such lung involvement. To emphasize the capriciousness of this tumor, although in 28 patients the metastases were present at the time of original diagnosis and in another 8 they developed within a year after nephrectomy, 4 patients were free of lesions for some time (two, two, three, and six years). A pertinent observation is the frequency with which the primary tumor invades the renal vein. In addition to the many cases in this series with intra- or extrarenal vein invasion, in 14 metastases went on to involve the vena cava.