Carcinoma, Renal Cell ; immunology ; pathology ; surgery ; Humans ; Keratin-19 ; metabolism ; Kidney Neoplasms ; immunology ; pathology ; surgery ; Male ; Middle Aged ; Neoplastic Cells, Circulating ; pathology ; Nephrectomy ; Vena Cava, Inferior ; pathology ; surgery

OBJECTIVETo study the clinicopathologic features of metanephric stromal tumor (MST), with emphasis on diagnostic criteria.

METHODSThe clinicopathologic findings in 2 cases of MST were analyzed and the literature of this entity was reviewed.

RESULTSCases of MST were unilateral and mostly centered in renal medulla. The tumor was separated from adjacent renal tissue by sharp and scalloped borders. Entrapped tubules and glomeruli were commonly seen within the lesion. The tumor cells were spindle to stellate in shape and arranged in a nodular pattern. On low power examination, alternating areas of high and low tumor cellularity were noted. Characteristically, there were onion skin-like concentric cuffs of tumor cells around entrapped tubules. The small intratumoral vasculatures showed irregular thickening ("angiodysplasia"). Immunohistochemical study demonstrated that the tumor cells diffusely expressed CD34.

CONCLUSIONSWhich the tumor cells around the entrapped renal tubules and blood vessels imparts a nodular appearance, as well as the tumor cells labbed for CD34 are the highly characteristic pathologic findings of MST.

Antigens, CD34 ; metabolism ; Diagnosis, Differential ; Female ; Follow-Up Studies ; Humans ; Infant, Newborn ; Kidney ; pathology ; Kidney Neoplasms ; immunology ; pathology ; surgery ; Male ; Nephrectomy ; Stromal Cells ; pathology

PURPOSE: To evaluate tumor-specific immunity and define the mechanisms involved in the cryoimmunologic response, we compared the tumor control efficacy and immunologic responses of cryoablation with those of surgical excision in a tumor rechallenge model. MATERIALS AND METHODS: Sixty BALB/c mice with RENCA tumors that were generated in the left flank area underwent cryoablation or radical excision. The mice successfully treated were rechallenged with RENCA or an undifferentiated colon carcinoma cell line, CT26, in the contralateral right flank area. The recurrence rate after tumor rechallenge in each group was then observed. To assess the immunologic response of each treatment modality, fluorescent-activated cell sorting (FACS) analysis and a cytotoxicity assay using 51Cr release were performed. RESULTS: After reinoculation of the RENCA cells, the rate of tumor growth was significantly higher in the surgical excision group than in the cryoablation group (94.4% vs. 11.1%, p=0.001). In the cryoablation group, the tumor growth rate was significantly increased after rechallenge of CT26 cells compared with RENCA (94.1% vs. 11.1%, p=0.001). The cryoablation group showed an elevated CD3, CD4, CD8 T, and natural killer cell count in the FACS analysis and also showed significantly increased cytotoxicity in the 51Cr release assay compared with the excision group. CONCLUSIONS: These results showed that cryoablation, compared to surgical resection, was more effective in preventing tumor growth after rechallenge with RENCA cells and that this response was tumor-specific, because the CT26 cells did not have the same effect.
Animals ; CD4-Positive T-Lymphocytes/immunology ; CD8-Positive T-Lymphocytes/immunology ; Carcinoma, Renal Cell/*immunology/pathology/*surgery ; Cell Death ; Cryosurgery/*methods ; Cytotoxicity, Immunologic ; Disease Models, Animal ; Kidney Neoplasms/*immunology/pathology/*surgery ; Lymphocyte Count ; Lymphocytes, Tumor-Infiltrating/immunology ; Mice, Inbred BALB C ; Neoplasm Recurrence, Local/immunology ; Neoplasm Transplantation