Juxtaglomerular cell tumor. With special reference to the tubular component in regards to its histogenesis

A left kidney tumor was found in a 33 years old female with diastolic hypertension and hyperreninemia. A yellowish white 6 X 4 cm tumor with capsule was located in the upper pole. Polygonal mesenchymal cells with Bowie-positive and rhomboid-shaped granules and occasional tubular component were identified. The diagnosis of J-G cell tumor was made. The first electron microscopic observation of the tubular epithelium showed immature features. 50-100 A microfilaments in the epithelium were identical to those reported in epithelium of Wilms' tumor. The results support that the tubular component is a tumor constituent and that the case is a biphasic tumor. Biphasic pattern and clinical characteristics of reported J-G cell tumor with tubular component are those of mesoblastic nephroma and adult multilocular cystic nephroma. Therefore, J-G cell tumor with tubular component would have to be classified as a metanephric blastema origin tumor as like Wilms' tumor, mesoblastic nephroma, and multilocular cystic nephroma.