Abstract
A case of Wilms' tumor diagnosed by the urinary cytology was reported. The characteristic cytological findings were as follows:
1) A gathering and/or scattering tumor cells, accompanied by many erythrocytes and a few lymphocytes, were observed in the smeared specimens of the urinary sediment.
2) The gathering tumor cells were small in size, large in N/C ratio and had rather obscure cellular borders. The cytoplasma of these cells showed faint staining of the light green. The nuclear shape of them were round or oval, accompanying granular or condensed chromatins. No obvious nucleolus was observed. These cytological features suggest an epithelial nature of the tumor cells.
3) The scattering tumor cells showed nearly round or spindle in shape. The cellular borders of them were rather well defined. The nuclear, nucleolar and chromatin pattern of the tumor cells were almost same as the gathering tumor cells. These tumor cells were considered to be the same in nature as above mentioned gathering cells, however, the scattering pattern of them resembled with stromal cells.
The combination of the gathering and scattering tumor cells induced the cytological diagnosis of Wilms' tumor. According to the classification of the Japanese Pathological Society, the histological diagnosis of the resected tumor was nephroblastoma (Wilms' tumor), nephroblastic type, focal nephroblastic subtype.
