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Renal oncocytoma: clinical and biological correlates
M R Licht1, A C Novick, R R Tubbs
1Department of Urology, Cleveland Clinic Foundation, Ohio 44195.
Abstract:
We treated 31 patients with renal oncocytoma. Renal cell carcinoma was found existing separately within the same or contralateral kidney in 10 patients (32%). Followup of 29 patients revealed 24 alive with no evidence of disease and 1 alive with recurrent oncocytoma, while 1 with coexistent tumors died of progressive renal cell carcinoma and 3 tumor-free patients died of unrelated diseases. Quantitative deoxyribonucleic acid analysis was performed on cell suspensions of fresh tumor by flow cytometry or by image cytometry on touch preparations from frozen tissue in 16 patients with renal oncocytoma. Ploidy analysis revealed all oncocytomas to be diploid. Frozen tissue immunohistology was performed using murine monoclonal antibody against human HLA-A, B and C (class I) antigens with the avidin-biotin peroxidase technique in 11 patients with renal oncocytoma. Ten oncocytomas did not express these self-recognition antigens and 1 was only weakly positive for antigen expression. In contrast, renal cell carcinomas strongly expressed HLA class I antigens. The high incidence of coexistence of renal oncocytoma and renal cell carcinoma has important clinical implications. Loss of HLA class I antigen expression by renal oncocytomas may provide an additional method for differentiating this lesion from renal cell carcinoma.
Insights
Renal oncocytomas often coexist with renal cell carcinoma. Loss of HLA class I antigen expression in oncocytomas may help distinguish them from renal cell carcinoma, aiding diagnosis.
Area of Science:
- Urology
- Oncology
- Immunology
Background:
- Renal oncocytoma is a benign kidney tumor.
- Renal cell carcinoma is a malignant kidney tumor.
- Coexistence of both in the same or contralateral kidney is observed.
Purpose of the Study:
- To investigate the coexistence of renal oncocytoma and renal cell carcinoma.
- To evaluate the expression of HLA class I antigens in renal oncocytomas.
- To determine if HLA class I expression can differentiate these tumors.
Main Methods:
- Quantitative DNA analysis (flow cytometry/image cytometry) for ploidy.
- Immunohistology for HLA class I antigen expression (monoclonal antibody).
- Analysis of patient data including tumor coexistence and outcomes.
Main Results:
- All renal oncocytomas analyzed were diploid.
- 10 out of 11 renal oncocytomas showed no or weak HLA class I antigen expression.
- In contrast, renal cell carcinomas strongly expressed HLA class I antigens.
Conclusions:
- A high incidence of renal oncocytoma and renal cell carcinoma coexistence was noted.
- Loss of HLA class I antigen expression is characteristic of renal oncocytomas.
- HLA class I antigen expression analysis may aid in differentiating renal oncocytoma from renal cell carcinoma.