[Clinical and pathologic analysis of 414 cases of renal angiomyolipomain in a single institution].

Objective: To study the different clinicopathological characteristics between classic and epithelioid renal angiomyolipoma, and the relationships between clinicopathological characteristics and biological behaviors as basis for clinical treatment. Methods: The clinicopathological and follow-up data for the patients diagnosed with renal angiomyolipoma between 2004 and 2011 were retrospectively reviewed and analyzed. Results: There were 414 cases of renal angiomyolipoma diagnosed over 8 years ago, accounting for 8.1% (414/5 287) of all renal parenchymal tumors. The patients included 122 male and 292 female (male-to-female ratio of 1.0∶2.4), mean age 44.0 years (range 15-74 years). Of these, 195(47.1%) tumors occurred in the left kidney, 212(51.2%) in the right kidney and seven (1.7%) were bilateral. Clinically, some cases presented with hypochondrial pain, hematuria or palpable masses. Histologically, 394(95.2%) were classic angiomyolipoma, 20(4.8%) were epithelioid angiomyolipoma; 54, 23 and 7 cases had hemorrhage, necrosis and cystic degeneration, respectively; and 5, 30 and 14 cases had perirenal fat invasion, atypical cells and polymorphic/giant tumor cell. There was a positive correlation between atypical cells and epithelioid tumor type, respectively. The other clinicopathological parameters did not correlate with histological type. Follow-up data was available in 360 patients, with follow-up period of 3 to 99 months. One case died from other causes. The remaining patients were free of disease. Conclusions: Angiomyolipoma is a common renal parenchyma tumor. Clinically, it is usually biologically benign. Histologically, it can be either classic or epithelioid types. The epithelioid type should be differentiated from the classic renal cell carcinoma, Mit family translocation renal tumor and renal hemangioblastoma. Atypical cells, more commonly found in the epithelioid angiomyolipoma, do not affect the clinical prognosis of patients.