Abstract
Renal cell carcinoma is known to show various histo-logical features including focal or diffuse sarcomatoidpatterns in rare instances. When the specimens are obtained from the sarcomatoid lesions alone, it is very difficult to make a distinct diagnosis of renal cell carcinoma. This report deals with two cases of sarcomatoid renal cell carcinoma without any urinary abnormalities, final diagnoses of which were made at autopsy.
In these cases, the specimens obtained in life were only cytological ones from metastatic lesions with sarcomatoid variant.
One case was a female aged 48 with a chief complaint of coughing. The clinical examinations revealed abdominal tumor and multiple lung and skin tumors. The cytological specimen was obtained by aspiration biopsy of the skin tumor. The other case was a female aged 54 who complained of abdominal distention. The clinical examinations revealed abdominal tumor with a marked retention of ascites. Cells in ascites were examined.
In both of smear slides from these two cases, multinuclear or giant cells were observed solitarily and scatteredly. The nuclear membrane was not thickened.
The nuclear margin was indented, with prominent nucleoli.
From these findings the cells were mostly suspected of “sarcoma” in origin. The cell margin, however, was not so obscure as that of many kinds of sarcoma cells and small vacuoles of various degrees were found in the cytoplasm.
Electron microscopically, the tumor cells were characterized by large cytoplasm rich in cell organellae and microfibrils. Numerous and irregular cell processes were also observed but microvilli were lacking at the cell surface.
Poorly developed desmosomal junctions were infrequently seen, which strongly suggested that the tumor cells might be epithelial in nature.
The autopsies of the two cases confirmed that the tumor cells were derived from sarcomatoid lesions of renal cell carcinoma.
