PURPOSE: The incidence of accidentally detected small renal tumors is increasing throughout the world. In this multi-institutional study performed in Korea, histopathological characteristics of contemporarily surgically removed renal tumors were reviewed with emphasis on tumor size. MATERIALS and METHODS: Between January 1995 and May 2005, 1,702 patients with a mean age of 55 years underwent surgical treatment at 14 training hospitals in Korea for radiologically suspected malignant renal tumors. Clinicopathological factors and patient survival were analyzed. RESULTS: Of the 1,702 tumors, 91.7% were malignant and 8.3% were benign. The percentage of benign tumors was significantly greater among those < or = 4cm (13.2%) than those > 4cm (4.5%) (p < 0.001). Among renal cell carcinoma patients, the percentage of tumors classed as stage > or = T3 was significantly less among tumors < or = 4cm (5.2%) than those > 4cm (26.8%) (p < 0.001). The percentage of tumors classed as Fuhrman's nuclear grades > or = 3 was also significantly less among tumors < or = 4cm (27.3%) than tumors > 4cm (50.9%) (p < 0.001). The 5-year cancer-specific survival rate was 82.7%, and T stage (p < 0.001), N stage (p < 0.001), M stage (p = 0.025), and Fuhrman's nuclear (p < 0.001) grade were the only independent predictors of cancer-specific survival. CONCLUSION: In renal tumors, small tumor size is prognostic for favorable postsurgical histopathologies such as benign tumors, low T stages, and low Fuhrman's nuclear grades. Our observations are expected to facilitate urologists to adopt function-preserving approach in the planning of surgery for small renal tumors with favorable predicted outcomes.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Female ; Humans ; Kidney Neoplasms/classification/*pathology/*surgery ; Male ; Middle Aged ; Neoplasm Staging

OBJECTIVETo analyze the clinicopathologic and immunohistochemical features and prognosis of papillary renal cell carcinoma (PRCC) in 19 cases.

METHODSA retrospective study was performed including reviewing the clinical documents and pathological sections of 19 cases of PRCC. Immunohistochemical staining were performed and follow-up was made in 16 cases.

RESULTSThere were 11 men and 8 women included in this study. The mean age was 52 years (range, 33 to 82 years old). Clinically, most tumors were found incidentally by physical examination because the majority of patients were asymptomatic. Histologically, the PRCC were characterized by varying proportions of papillary and tubular architecture covered by single- or multiple-layer of tumor cells with scanty or voluminous basophilic or eosinophilic cytoplasm. Foam cells and psammoma bodies were seen in some papillary cores and stroma, and the cytoplasm of some tumor cells contained hemosiderin. Of these 19 patients, 12 (63.2%) and 7 (36.8%) were diagnosed as type I and type II PRCC, respectively. The Fuhrman nuclear grade in all the type I PRCC was grade 1 - 2, significantly lower than that in the type II PRCC. Immunohistochemically, the PRCC often showed positive immunostaining for vimentin, EMA, CKpan, CK7, CD10 and p504s. Among the 19 patients, 16 were followed-up from 2 to 67 months. The distant metastasis, including lung, liver and bone metastases were detected in 3 patients at 3, 8, and 9 months after surgery, which were all of type II PRCC. Two patients died of other diseases. The other 11 patients were alive without recurrence or metastasis.

CONCLUSIONTwo subtypes of PRCC show different features of morphology, immunohistochemistry and prognosis. The type II PRCC tends to have unfavorable prognosis in comparison with type I PRCC. The presence of higher nuclear grade, sarcomatoid elements or clear cell carcinoma structure may indicate an aggressive behavior and poor prognosis.

Adult ; Aged ; Aged, 80 and over ; Bone Neoplasms ; secondary ; Carcinoma, Renal Cell ; classification ; metabolism ; pathology ; surgery ; Female ; Follow-Up Studies ; Humans ; Keratin-7 ; metabolism ; Kidney Neoplasms ; classification ; metabolism ; pathology ; surgery ; Liver Neoplasms ; secondary ; Lung Neoplasms ; secondary ; Male ; Middle Aged ; Mucin-1 ; metabolism ; Prognosis ; Racemases and Epimerases ; metabolism ; Retrospective Studies ; Vimentin ; metabolism