Malignant renal neoplasms are one of the most difficult disease for correct clinical early diagnosis. Occult growth and metastasis of the tumors before the onset of symptomes related to the primary renal lesion seem to make clinicians feel the limit of modern medicine.
On the other hand, Case has reported the incidence of renal cancers in Japan is lower than that in America or in England. In spite of a number of case reports published up to date, little work has been done in geographical and statistical study of renal cancers in Japan.
511 cases of carcinomata of the renal parenchyma and renal pelivs are accumlated in all reported 87, 425 necropsies in Japan for the past 7 years from Nihon Boken Shuho Vol. 1-Vol. 7. This group ranks seventeenth in order of frequency among all carcinomata, and represents 0.58 percent of all necropsied cases, and 1.50 percent of all malignant neoplasms.
About 80.2 percent of malignant neoplasms in the kidney are the renal adenocarcinoma (so called hypernephroma, clear cell carcinoma, Grawitz tumor).
Statistical analysis of renal cancers, particularly of the renal adenocarcinoma has been done for the points of incidence, age, sex, clinical diagnosis, the site of metastasis, and the services where the patients were cared.
The age range of patients with renal adenocarcinoma extends from 6 to 84. Although each age group of the all necropsies has not been standarized to a common base, the peak incidence of renal adenocarcinoma centers arround the sixth decade. The ratio of male to female with this neoplasm is 2.8:1. Clinically, 222 cases of this disease (about 54.4%) were correctly diagnosed as renal malignant neoplasm.
Among the incorrect clinical diagnoses “primary lung cancers” 20 cases, “primary bone tumors” 20 cases, “hepatomas” 10 cases, “brain tumors” 9 cases, and “gastric cancers” 9 cases are of conciderable significance. The site of metastases detected at autopsy in 409 patients with this desease are the lung in 275 (67.2%), lymphnode in 222 (54.2%), bone in 150 (36.7%), liver in 144 (35.2%), and the brain 35 (8.5%) etc.
The orders in which specific lymphnodes and specific bones are involved by metastases is indicated in tables.
At the time of autopsy, the cases from the urological services comprise only 14.7 percent of this disease.
About 28 autopsied cases of renal adenocarcinoma in Keio University, clinico-pathological review is done for the points of chief complaints, clinical symptoms and signs, clinical examination datas, histological classification, prognosis and relations between them.