This article is the sixteenth and last oj a series to be published by the American Medical Association in cooperation with the American Cancer Society. The series is designed to aid in the early diagnosis of cancer and thereby to gain more effective results in treatment.
CANCER OF THE KIDNEYIn two periods of life cancer of the kidney occurs, in infancy and in aging adult life. In infancy occurs one of the more frequent cancers of childhood, Wilms' tumor or infantile embryoma. This is a silent tumor and is highly malignant, with a serious and impressive record of fatal termination. More frequently, there occur in middle-aged or in elderly persons the various epithelial carcinomas of the kidney which are often silent until they reach considerable size and usually show their presence by blood in the urine. The early recognition of renal cancer in both these age groups is a problem for the medical practitioner, because by early surgical removal of the affected kidney lies the correction of an otherwise fatal course of the disease.Carcinoma of the kidney ranks third in frequency among the tumors of the urogenital system, following carcinoma of the bladder and of the prostate A few rare tumors of the kidney, not epithelial in origin, such as fibrosarcoma and leiomyosarcoma arise from the renal capsule or pericapsular tissues. The usual cancer is one epithelial in origin, originating from the renal parenchyma or from the epithelial lining of the pelvis. The latter, a specialized epithelium, is in the lining of the ureter and bladder, and all the tumors arising from this specialized epithelium are of similar class, whether from renal pelvis, ureter or bladder. The tumors occurring from the renal parenchyma itself are specific tumors of that tissue.The formation of the renal parenchyma is of two origins: (1) the part formed from the renal blastema is that part above the "connecting piece" in the system of Henle and (2) the portion below the connecting piece is from the wolffian system and actually is of the same embryologie origin as are the renal pelvis and the ureter. The separate origin of the two parts of the renal parenchyma would lead one to suspect that two different types of tumor cells would occur. Two different types of tumor cells do occur, one a clear cell and the other a granular cell. One or the other may be the predominant cell in a tumor, or sometimes a part may be of clear cells and another part of granular cells. There is, however, as yet no acceptable evidence as to the origin of either the clear cell or the granular cell except that they both are undoubtedly of renal origin. It is also true that clear cell carcinomas occur more frequently in the cortical areas and granular cell tumors more often in the medullary and corticomedullary areas. The clear cell carcinoma may originate from the renal blastema cell; its growth action to some degree suggests such origin, and the granular cell arising from the wolffian system resembles the infiltrating carcinoma of that system.Small cortical adenomas of the kidne...
