LAUSR

Micro‐Abstract We evaluated the clinicopathologic characteristics and prognosis of Xp11.2 translocation renal cell carcinoma (RCC) from a multicenter study. This rare neoplasm had more aggressive clinicopathologic features to involve lymph nodes at diagnosis. The age of incidence had a bimodal distribution. In older patients with onset age older than 45 years, Xp11.2 translocation showed a significantly worse prognosis than clear‐cell RCC. Background: We evaluated the clinicopathologic characteristics and prognosis of Xp11.2 translocation (Xp11.2t) renal cell carcinoma (RCC) from a multicenter study and compare them with clear‐cell RCC using a propensity score matching analysis. Patients and Methods: Between 2004 and 2013, 8384 consecutive patients from 7 institutions who were diagnosed with RCC were reviewed, and the pathologically confirmed Xp11.2t cases were enrolled. The oncological outcomes of Xp11.2t were compared with those of clear‐cell RCC by selecting matched cases using 1:3 propensity score matching methods in a precollected clear‐cell RCC data set from our hospital. The patients were divided into 2 subgroups on the basis of age of onset, either before (early) or after (late) 45 years old. Results: Xp11.2t was found in 61 cases, corresponding to 0.72% of RCC cases for the 10 years. The mean age was 38.2 ± 19.4 years, and the mean tumor size was 6.2 ± 3.9 cm. The Xp11.2t cases were at more advanced stages and showed tendencies to involve lymph nodes at diagnosis. After the matching, there were no significant differences in recurrence‐free and overall survival compared with clear‐cell RCC. The age of incidence for Xp11.2t had a bimodal distribution, which was most common in the 30s and smaller peak in the 60s. Xp11.2t corresponded to a significantly worse prognosis for overall survival in late onset (after 45 years) subgroup (P = .038; hazard ratio, 3.199; 95% confidence interval, 1.065‐9.609). Conclusion: This neoplasm has more aggressive clinicopathologic features at diagnosis. In older patients with onset age > 45 years, Xp11.2t showed a significantly worse prognosis than clear‐cell RCC.